Step Mania is an open-source game project that recreates the popular console dance game experience for computers running various Windows, Mac and Linux operating systems. With a free download and lots of content, Step Mania is a lot of fun.
Gadget blog TechEBlog put together a list of ten truly odd gaming controllers. Standouts in strangeness include the Wii knockoff SplitFish Glide FX, the Resident Evil GameCube chain-saw controller and the (pictured) PS2's "PachiSlot" controller.