The Raspberry Pi is a credit card sized Linux computer that costs about $30 (some versions are only $10). Because they are cheap, tiny, and versatile, they are an excellent basis for lots of different projects. Creative Projects with Raspberry Pi (out today!) by Kirsten Kearney and Will Freeman is loaded with build instructions, resources, and pointers to a bunch of cool projects: coffee roasters, weather stations, mobile phones, handheld gaming consoles -- 35 in all.