I have two Dreamcasts, but I haven't really done anything worth mentioning yet. My plans for one of them:

• Paint it (done, it's yellow)
• Cut out an opening to watch the CD spin (done, poorly)
• Add VGA port (parts ordered)
• Overclock with switch (parts ordered)
• Serial cable (parts ordered and then killed)

I ended up getting busy with other things, so who knows when this list will be complete.

I have a couple of VMUs, too, and I modified one of them to attach to a PC parallel port to transfer games and stuff, but I broke it, so that's another thing that'll get done one day...but not today.