I like to play a game called "Troll the Internet"
You pick some category (music, books, movies, etc) and then ask a question along the lines of "Which is better?". You can even do it with entire categories (e.g. "What are the best songs to have in my music collection?" "What are the best books to read?")
It's hilarious watching the infighting and attempts to justify responses to a subjective question.
The game has gotten a bit out of hand though. I've even seen it being played on popular tech forums like "Slashdot".
Nah, I prefer old school trolling where you say something that makes the "I've got to correct this idiot..." urge overpower the "The can't be serious..." rationality. For example:
As a scientist, I enjoy science fiction but am upset by how often they get simply science laws wrong. For example, I am a big Star Trek fan and overall find their science plausible. However, whiner the shuttle craft passes in front of the Enterprise it cases a shadow. In a vacuum. Don't they realize you won't get a shadow in the vacuum of space?