A free web game
run at www.pyroto.com.
Pyroto is about trivia, and other stuff.
You answer questions to gain levels as well as to ascend up the Mountain.
It's apparently something that migrated from a BBS game; they say they've
been running this game since 1986.
I'm now about 1/3 of the way up the mountain, and it has turned out to be an interesting experience.
The game is designed to be a social one; you have to send messages on their internal message boards in order to proceed. Doing so more than the bare minimum necessary may be helpful, both in gameplay as well as in working with others to figure out difficult questions, etc.