Mods are one of the greatest things about PC gaming. Just taking a quick look at ModDB will reveal numerous maps, models, and total conversions for just about any game released. As I have mentioned in a past blog entry and Dr. Jerz has mentioned in this article, some mods even go on to a commercial release. They are an interactive form of fan fiction or art or a short film. Many games now include an SDK (software development kit) allowing just about anyone to try their hand at creating something. This strengthens the games community and the life of the title.