I stumped him with Ender from Ender's Game, I was surprised. But after you stump the genie it asks you for the name of the character you were thinking so it will probably get him right the next time.
He also got Goliath from Gargoyles, Lucy (the fossil), Thorin Oakenshield (probably a bad time to use that one :P), some poet, God, Illuvatar, Boss Nass, himself, and some more I forgot. However he didn't get Raymond Fosca from a novel; stumped him on that one at least^^
illuvatar? so you have read the Simarillion? (yes I know it is misspelled)
I easily stumped him with Jacen Solo, he ended up getting some character from the Dragonriders of Pern series.
p.s. would you define the force as magical powers?
I remember I used to play this in math class. The weird part is that it once came up with some inappropriate questions. As in adult +.
Yea I had the same thing happen when I was thinking of Macbeth as the character he had to guess. Was very weird since it was a string of innapropproriate questions and then I never saw the questions again.