Help me, Americans?

[lilacsigil]

What do you call the game where you kick a little bean-filled soft ball around with your feet? Played by students everywhere.

Is it hackeysack? Hacky Sack? Hackysack? Footbag? Foot Bag? Kickybag (from The Sims 2)? Something else entirely?

What would a teenage boy from New York call it in 2006?

Thanks for any enlightenment you can shed on the issue!