Quoted from John_I:Weebly is a nice alternative if you want to save a little money or be able to use your own ROMs.
The Weebly board has expanded ROM and RAM addressing allowing anyone who wants to write their own game code/rules to go to town and not be restricted to the limited factory ROM/RAM space on the original MPU board. This includes using Olivers homebrew game code that requires expanded ROM.
The spare 512kbit ROM socket on the Weebly board allows you to program up to 60kByte of game code (factory board is 8kByte), and onboard RAM expanded to nearly 4kByte.