SparkFun sells this squirrel cage blower:
https://www.sparkfun.com/products/11270
I bought one and used it for aerodynamic levitation.
http://i.imgur.com/kSCQ6oa.jpgIt’s very simple to do, just point the blower straight up and put a balloon in the path of the air flow.
This has been done before; it’s actually a common demonstration in science classrooms, where it’s usually done with a hair dryer and a ping-pong ball. But I like the squirrel cage blower because it’s much quieter than a hair dryer. Also, as you can see in the photo, I put a towel under the blower, and that makes it even quieter.
Hopefully others will be inspired by this, replicate this, and build something even cooler! If you have any questions, just ask.