Here is a quick flash test to see if you're tone deaf or not - you listen to a series of musical phrases in pairs, and have to decide if they're different or the same.
It was created by Jake Mandell, who is a true renaissance man. Originally a producer of some repute, he also worked for Native Instruments in Berlin, helping to develop Reaktor and Absynth. Now he's at Medical School, specialising in Neurology. (Full bio here). The Tone Deaf Test is "purposefully made very hard, so excellent musicians rarely score above 80% correct". This is clearly true, because I'm certainly not an excellent musician, and I got 83.3%. How about you? (Thanks, Stefan)