A lot of games come with ways to create more content, maps etc. Farcry 2, Crysis, Fallout 3, Morrowind... Oblivion? Anyway, me and a friend recently started playing with the farcry 2 one, and although it is intuitive and easy to use, it's very limited. Only 15 explosive things, can't put weapon spawns, can't spawn enemies (AI), and the tools do have limitations. However, it's the only one we really have experience with, so I guess I'm saying that one. At least it's easy. We did find the Crysis one, which seems much better, but didn't get an opportunity to try it much. What's your favourite editing software for a game, free, and why?