Here's a quiz that gives you forty video game screenshots and asks you to guess the game it comes from. What's extra nice is that it is quite generous on most of the answers i.e. if it's from a series you can just give the name of the series rather than the particular game.
There are 40 shots and I got 27 right - if you know what 1, 2, 4, 5, 6, 11, 16, 18, 22, 23, 26, 29 & 38 are leave a comment. A couple of those look familiar but I can't remember the names - and 38 I'm almost positive what it is but it won't take my answer. Bah! ;)