I like to describe it as a mixture of gymnastics, dance and "hackey sack". If you want it to sound sportier you can drop the dance - or exchange it for soccer. Partcularly in australia where there are alot of disenfranchised soccer players (although the new a-league is changing that - however it doesnt change the fact that rego is rediculously expensive and the organisation of many competitions is sub standard) trawling soccer training for undiscovered footbag talent may be the way to go. Alot of teams play indoor in the summer off season and train in squash courts. This is why i suggest pitching it a little in that direction. I guess the problem with this is that we're don't want it to be thought of as a "soccer training aid" so you need to be careful about you're approach.
People are asking me this all the time when I tell about my hobbies.
I might do a short video soon which will be answering without any words to the question "What is Freestyle Fotobag?"
That is, if Felix films and edits it.