I forgot to post this! A couple of weeks ago I was looking around the web for a computer program that would keep score automatically, but all I found was BridgeKeeper, which only scores duplicate bridge, and only works on Macs.
I reused the scoring mechanism from BridgeKeeper to write a scoring program for rubber bridge: Rubber Soul. Try it out at home this weekend! Let me know if it gives you any trouble or if you have any suggestions for improving it.