Grid swarms

These are a very cool use of the Gumstix computers (which I think are themselves awsome)

http://linuxdevices.com/news/NS2142584362.html
http://gridswarms.essex.ac.uk/index.html

My favorite
http://cswww.essex.ac.uk/staff/owen/research.htm#The%20Flying%20Gridswarm,%20and%20the%20UltraSwarm