I strap these to the top of my milk crate mining rigs.  No kidding, works great.

http://www.amazon.com/Honeywell-Whole-Circulator-Floor-HT-908/dp/B001R1Q0OG/ref=sr_1_1?ie=UTF8&qid=1391461302&sr=8-1&keywords=whole+room+air+circulator