One of the fun thing on linux, that i do is mame game.
mame emulator is in ubuntu repository for sometime, the interesting is, there is no frontend for gnome. But a very good front end for mame on linux is, kxmame.
to install on ubuntu, run
sudo apt-get install xmame-sdl xmame-tools xmess-sdlto install kxmame just run
sudo apt-get install kxmamehere's the catch, you need to find the rom yourself, and you will need to find the bios too