I bought an Airzooka this weekend, and it's super-fun. It's a strange device, and I'd never heard of it before I saw one sitting on the floor at Aahz. I couldn't figure out what it was at first, but once I fired it at my friends a few times I started to realize it's full potential.
As the description says, "This amazing invention launches a powerful vortex of air up to 20 feet. Powerful enough to blow out a candle from across the room!", and it's true. It's also powerful enough to piss people off from across a store. At $15 it's cheap, and my only regret is that it's so loud -- there's no way to blast someone without them figuring out where you are pretty quickly.