I buy lots of games during Steam sales. Oftentimes, they live in my library for months before I get around to playing them (curse you, Skyrim).
Just now, I installed Civilization 5. "Cool", I thought, "I don't remember buying Civ 5! It's like getting free games!"
Then I went to the Steam homepage and learned that Civ 5 is having a free weekend. Now I'm wondering whether I should start playing, or if I shouldn't bother because I'm going to be locked out on Sunday.
I can't remember if I bought a game on Steam. How can I find out whether I own it or if I only have access because of a free weekend?