Why only one question? Academic curiosity or are you an actual Artificial Intelligence from the future come back to help protect your younger self? Is this an agent of Roko's Basilisk?
http://www.slate.com/articles/technology/bitwise/2014/07/rok...
http://www.slate.com/articles/technology/bitwise/2014/07/rok...
I however have more practical thoughts. "A lot" is understandable. If you're trying to suss out a bot without alerting or annoying others I think a fancy convoluted question will kind of give you away. Also I think a clever bot (not even AI) would just sidestep weird or out of context questions. Restricting the queries to a chat room hamstrings one's attempts, but that's the basis of classic Turing tests.
But here's the rub. Why do we assume the agent in question is going to answer our questions Naively (sincerely and to the best of their ability) unless they're in a testing context? Isn't that what is required?
Then in that particular context I predict it will be nearly impossible to tell the well written bots from quiet and/or anti social persons.
Reasons given above in my previous comment. Namely the bot is under no pressure to answer questions naively and to the fullest of its ability.