The Badland Cafe

I'm writing an urban fantasy book about the Unseelie
Court (where the "bad" faeries live in Irish folklore) and faeries are notorious
for playing games, so I'm trying to think of one. The main character, Bambi,
is playing this game against a Fae named Caaleb, trying to free a
psuedo-vampire, Damien. I have a vague idea of what this game entails, but it's not
fleshed out yet and I'm having serious issues with it.
It's got to have something to do with riddles. Originally I was thinking
Caaleb throws a riddle at her, she answers it, throws one back at him . . .
until one is stumped and can't think of the answer - but that's pretty boring.
I think that's gonna be the basic idea, but I need a twist to it, something interesting that'll keep the reader hooked.
Or if anyone has an idea for something completely different, I'd love to
hear it. :)
Thanks!