Kippo is a lot of fun indeed.

Just out of spite, what would be the free/opensource alternative?

While I would love to build a MAME machine myself, I still havent got around to it (need to wait a while till I can buy a decent computer to throw in there). So in the mean time, for the last week, I've started on a backyard air hockey table. The thing is about half way finished; I just need to mount the fan to the bottom and build the legs for it. While there are plenty of MAME related websites you can google up, try finding one on a homebuilt air hockey table. If you cant, i'll tell you why: air holes. I put a sheet of peg board on top of my table and drilled 4608 of them yesterday, one every inch. It took about six hours and i'm probably going to have carpal tunnel syndrome. Anyway, hopefully I'll finish the thing tomorrow. Another project I worked on last year was building a metallic DDR pad. It's pretty nifty, I put some LED lights underneath it, which I havent seen anyone else do. Things works alright, but i never use it anymore. Anyway, sometimes it's the journey, not the destination.. just remember that when you're building your machine