A cool ISA I/O card designed for dumping console ROM. If I had any idea how to use a soldering iron this is the first thing I would make.

The design plans come with DOS software (with source code), and you can dump NES, SNES, Gameboy, and Sega Master System cartridges. Other types of cartridge adapters and dumping software can be made for this, obviously, but you'll have to come up with them yourself.