http://us.akinator.comI tried to stump it, but it has a decent DB of data behind it.
My kids tried Terminator and Spongebob, (it guessed them in less that 10 questions)
"V" from Vfor vendetta took about 10.
Neo from The Matrix was pretty quick also.
Hiro Protagonist, the main character in "Snow Crash" (great Sci Fi book), 30 questions, but did find it.
R