There’s a nifty little website out there called Dave’s Mapper. Basically what this web-based tool does is randomly generated classic Dungeons & Dragons style dungeon maps for use in pen and paper role-playing games.
The generation itself is pretty simple as you can propably see: It always uses the same points to connect the different tiles. However there’s quite a bit of content and it’s still growing since creating these “geomorphs” (which is what the tiles they use are called) seems to be a fun hobby for some people.