Freestyle footbag

Freestyle Footbag is a footbag sport where players demonstrate their abilities by performing sequences of acrobatic tricks. The ending position of the bag on one trick becomes the starting position of the bag on the next trick. Tricks are created by combining different components between contacts (stalls or kicks, usually stalls). Components can be spins, dexterities (wrapping a leg around the bag in mid-air), or ducks (letting the bag 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 a near-endless list of tricks.
Competition Events.
In competition, there are several different freestyle events. 
Routines.
In this event a player choreographs and executes a routine to music. Much like figure skating, players are given scores for technical and artistic merit. These scores take into account choreography, difficulty, variety, and execution. At the open level, singles routines are 2 minutes long, doubles routines 3 minutes; at the intermediate level and in women category, routines are 90 seconds.
30 Second Shred.
Or "Shred 30" is purely technical. Competitors have to execute as many unique, difficult tricks in a 30 second period as possible. Their score is calculated with a mathematical formula, which takes into account the average difficulty of the run, and penalizes the players for repeated moves. Dropping the bag lowers the player's score in 2 ways: it lowers their difficulty ratio, and decreases the number of tricks they can fit in 30 seconds. The formula is adds + adds*uniques/contacts.
Sick 3.
The objective of this event is for players to link three hard tricks together in the most impressive way possible. Players are usually given between 5-7 attempts to land a combo, within a maximum time frame of 2 minutes. This event is often judged by a panel of judges, who sometimes use videocameras to verify that moves were hit cleanly within the combo. Judging is purely subjective.
Sick Trick.
In this competition, the most difficult assortment of components is put into one move and judged subjectively by difficulty, form, and cleanliness. Usually the competitor is given 3-7 tries which is at the competition director's discretion
Rippin' Run.
In this competition, a minimum of two players start a guiltless string (a series of moves with a minimum requirement of 3 components (adds) in between contacts) and try to outlast each other. Players are eliminated and the winners progress to the next round, just like in the single-elimination tournament.
Circle Competition.
Or "Circle Comp" or just "Circle" for short is relatively new compared to other events, Circle Comp was invented by Ianek Regimbald and Sebastien Duchesne of Montreal, Quebec, Canada, and Eliot Piltz of Vancouver, British Columbia, Canada, with input from several other competitive players. In Circle Comp, the total pool of competitors are divided into smaller pools (or Circles, giving the event its name, and also representing how freestyle footbag is typically played), usually of no more than 4 players. Each player in the circle takes a turn with the bag, until they drop. The bag is then passed to the next player, who takes their turn, and so forth. There is a limit to the number of times the bag will go around the circle. For instance, there may be three difficulty rounds followed by three variety rounds, though organizers of different events may revise the structure of the format in different ways. Players are evaluated subjectively by a panel of judges.
Components (ADD Categories).
Tricks performed while playing freestyle are made up different add categories. ADD is an acronym for "Additional Degree of Difficulty". 
A toe stall would be a 1-ADD trick. TOE [DEL]. A "clipper" is a cross body inside delay CLIP [XBD][DEL] and is worth 2-ADDs. A cross-body sole delay XBD_SOLE [XBD][UNS][DEL] is worth 3-adds. The more adds, the more possible permutations there are for tricks. Moves have been performed up to 9-ADDs (Chilly-Philly Sauce). There are 5 ADD types 
ADD classification.
If you are a player who can successfully combine multiple ADD level tricks in one "String" or "session" than your playing difficulty can be classed as follows.
Freestyle trick fundamentals.
Kicks.
There are 3 fundamental kicks that are used in freestyle. These kicks are:
Stalls.
Once a player has mastered these tricks, they generally move on to stalling/delaying the footbag. This is where the footbag stops on part of the body. It is done to gain more control of the footbag, or to set up prior to a trick. Some of the simpler stalls found in freestyle are:
Other Components.
Move Elements
Combining Concepts.
Spins can be added to dexterities to create moves like spinning down.
Acronyms and Jargon.
Here is a list of various terms and concepts, these do not include actual trick names.