Everything There is to Know...
Just to give credit where credit is due, a lot of this information came from a summary from answers.com, but I filtered through it for what I found to be more interesting and important. Below you'll find information about the actual footbag itself, modifying shoes and laces for hacky sack, a little bit of information on freestyle footbag and circle kicking, some fun games to play, and finally some world records and champions. If you want to learn more about these other topics, head to their own pages: Footbag Tricks - How to Hacky Sack, Footbag Care, Footbag Videos.
The only piece of equipment necessary to play footbag is a footbag, though shoes with optimized kicking surfaces are recommended by most advanced players. There are several differences between footbags which will affect how they play, thus making different bag choices necessary for different sports.
For circle kicking, it is very common to use a crocheted footbag, which is usually filled with plastic beads. Casually, footbags are often differentiated as normal (indicating a plastic-pellet filling), or as "dirt bags" or "sand hacks" (indicating a sand filling). Sand hacky sacks are typically considered ideal among casual, beginning, or intermediate players, who use them as a learning tool, as they are easier to control and stall than a crocheted bag filled with plastic pellets.
In the freestyle footbag discipline, a 32 panel bag is the generally accepted standard (the number of panels on commercially available bags can range from 2 to 120 panels). Most professional stitchers use some combination of Plastic Poly Pellets, BB's, steel shot, lead shot, seed bead or even tungsten shot. Bags usually weigh between 40 and 65 grams, depending on the type of filler and amount of filler used. 32 panel bags do not stall as easily as a hacky sack with less panels, but set truer from the foot, allowing for more complex tricks. Professional footbags are usually made out of the fabrics ultrasuede light, facile, or amaretta. While these bags can last a long time with proper care, they are quite fragile relative to their more common crocheted cousins. Bomb Footbags uses Japenese Amara because it is an amazingly soft fabric, yet still quite durable.
Most advanced freestylers wear Adidas Rod Laver tennis shoes, Adidas Clima Cool 1s or lowtop Reebok G-Unit G6s while playing. However, any shoes with nice flat surfaces are great. Several shoe modifications are common in freestyle footbag. In order to make toe stalling easier, many players use special lacing patterns that pull apart the sides of the shoe near the toe area, creating a broad, rimmed platform. Modified lacing is augmented by cutting away the stitching that joins the row of eyelets to the toe. The area that is created by completing these modifications is called a toe box. Shoes can be further modified for freestyle footbag by removing layers of fabric from the inside, outside, and toe surfaces. These modifications are advantageous because they allow players to more accurately feel the bag on their foot.
Freestyle Footbag is a sport in which the object is to perform tricks with the bag. The ending position of the footbag on one trick becomes the starting position of the footbag on the next trick. Tricks are created by combining different components between contacts with the bag (contacts can be either stalls or kicks, though stalls are more frequent). Components can be spins, dexterities (using a leg to circle or cross the footbag's path in mid-air), or ducks (letting the footbag pass a few inches above the neck). Contacts are usually on the inside of the foot behind the opposite support leg (Clipper Stall) or on the toe, however, many inventive possibilities remain and are used to create an endless list of tricks. Freestyle moves list have been developed trying to follow the trend. Various styles have developed as the sport has become more popular. Players can choreograph routines to music, alone or in pairs, executing difficult moves in sync with the music—the result is something like a cross between rhythmic gymnastics and figure skating. There is an annual footbag world championships held each year. The current freestyle world champion is Milan Benda, of Czech Republic.
Circle kicking, also known as playing hacky sack, is the most common game played with a footbag, and it is the game people refer to when they talk about "Hacking it up." Players stand in a circle and keep the bag moving around the circle, with the goal of keeping the bag from touching the ground. A "full hack" is achieved when every person that is in the circle hits the footbag at least once with out it hitting the ground. It is generally not celebrated until that round of hacking is over. It can also be continued and once the last person has hit the bag, the players in the circle can attempt another "full hack" and if successful, the Circle can achieve a "double hack" and can continue on to "triples" and so on until the bag hits the ground. Circle kick is generally accompanied by an unwritten set of etiquette guidelines designed to keep the game fun, friendly, and open to everyone including new players. The most basic rule is to respect all other players. Some other general guidelines include picking up the footbag after you drop it or kick it away, rather than having someone else retrieve it; not serving the footbag to yourself; not spitting in the circle; and not hogging the footbag (often called jestering, or the player may be called a hack-hog) and making sure to pass the bag to players who have not gotten it recently. Most circles are very open to new players and will not ostracize anyone for being less coordinated or well practiced than the rest. Some circles have an unwritten rule that there is no apologizing when a person drops the footbag. This guideline is designed to keep the new players from feeling as if it is their fault that the game is slow, and it keeps the experienced players from having to constantly reassure the new players that it is not their fault, which can get tedious. Also when and if the "Kicking Circle" gets large to the point that it becomes difficult to get the footbag to the opposite side of the circle (usually around 10 or more players) it is common for a player to give up their place on the outside and move to the center of the circle (Usually a more experienced player will take this position) when this happens the center player is most often referred to as the "Nipple". Variations on circle kicking are numerous and spontaneously created.
Horse is a game that can be played with any number of players and is a great way to improve one's freestyle. One of the players performs any freestyle move he/she chooses, then passes it on to the next player who then attempts to perform the same move. If he/she performs the move correctly then that player performs a different move of their choice, and then passes it on. If he/she fails to do the move then they get a letter "H"(if they miss again on the next round they get an "O") and passes it on to the next player who chooses a new trick. Once a player spells the word "Horse" they are out. Slaps is a game in which players must keep the hack up for a chosen number of kicks (charges) and slap the hack at someone in the circle when that many kicks has been reached. If a player is hit by this slapped hack then he/she is out of the game. However if the player who has been hit kicks the hack after being hit, or if any other player kicks it, they have saved themselves from the out and may attempt another "kill". Circles may decide for people to have a certain number of lives before being kicked out of the game but it is generally one. Instead of slapping the hack, a variation calls for the player to kick it to the other players once the charge is reached. This variation is commonly known as "Kill." War is a game for any number of players. The footbag is served and after a predetermined amount (usually 3) of kicks (whether by one person, or collectively as a group) everyone tries to catch it. The person who catches the footbag throws it at one of the other players who try to either dodge or catch it. If the footbag hits someone they are out, but if they catch it the person who threw it is out. The game can be played with any number of outs. Also known by the names "Pelt", "Three Balls of Fire", "Three Hit Kill", "Three Hack Wack", and "God". The X is a game that can be played with three or more people. The first player to "mess up" the hacking circle becomes the X. They are the X until a different player messes up, then that new player becomes the X. If the X serves it to a player, then that player must catch it. If they play the X's serve, then they become the X. You may serve it to the X in order to make them mess up again. If someone is already the X and mess up again they get one strike. Once a player receives a strike, it goes back to no one being the X, until a player messes up the circle again. Once a player gets three strikes, they are eliminated. Also known as "the Bitch".
The Guinness Book of World Records has recognized footbag consecutives world records since the 1980s. There are several categories of records, all variants of the "consecutives" discipline. The current records are listed below.
* Men's Singles footbag o Ted Martin o Total kicks: 69,812 o Total time: 7 hrs. 38 min. 22 sec. o Date of record: November 15, 1995 o Official event: Classic Footbag 1995 (Chicago, Illinois, USA)
* Women's doubles footbag consecutive o Constance Constable/Tricia George o Total kicks: 34,543 o Total time: 5 hrs. 38 min. 22 sec. o Date of record: February 18, 1995 o Official event: Heart of Footbag Freestyle Tournament (Portland, Oregon, USA)
* Open doubles footbag consecutive o Tricia George/Gary Lautt o Total kicks: 132,011 (previously 123,456) o Total time: 20 hrs. 34 min. o Date of record: March 21 & 22, 1998 o Official event: Chico, California, USA
* Women's singles consecutive o Constance Constable o Total kicks: 24,713 o Total time: 4 hrs. 9 min. 27 secs. o Date of record: April 18, 1998 o Official event: California Athletic Club (Monterey, California, USA)
* Open Singles Consecutive
o Ted Martin
o Total kicks: 63,326
o Total time: 8 hrs. 50 min. 42 sec.
o Date of record: June 14, 1997
o Official event: 1997 Midwest Regionals (Chicago, Illinois, USA)
* Largest footbag circle o Andy Linder and 945 of his friends o Total players: 946 o Date of record: July 6, 2001 o Official event: Cornerstone Festival (Bushnell, Illinois, USA)
* Open Singles Freestyle - Milan Benda (Czech Republic)
* Open Doubles Freestyle - Wiktor Debski (Poland) and Gosia Debska (Poland)
* Mixed Doubles Freestyle - Tomasz Ostrowski (Poland) and Malgorzata Nycz (Poland)
* Women Singles Freestyle - Tina Aeberli (Switzerland)
* Open Circle Contest - David Clavens (USA)
* Open Shred 30 - David Clavens (USA) Net * Open Singles Net - Tuomas Kärki (Finland)