A new Dreamcast port "Neverball" is being released in it's alpha version.
It looks and feels alot like Monkeyball so if you like those types of games it might be worth a CD-R. Here's a video of someone getting beat down while playing. It takes nerves of steel to play this game...
Here is the download link from the DCEmu website. Please note this game is still in it's preliminary stage so expect some bugs. It's in .CDI format so you will need Discjuggler, Alcohol 120 or Bootdreams to burn it.
As a bonus video here is a look at the PS controller converter. It takes note that the PS Guncon, fishing controller and twin stick will not work on the Dreamcast even with the converter. I just thought this video was interesting. Some day I will have to invest some cash in a PS2/DC converter for the dance mat.