In the mid 80s Atari launched the succesful ST home computer, after fighting for the rights to the Amiga with Commodore. It had to fight against the superior Amiga but found it's own niche market, the music industry. The computer came equiped with a MIDI-interface to connect to keyboard. In the UK it was a quite succesful games computer as well.

OIDS.X

ST games were often conversions of Amiga games. Much about this can be found at Atari.ST. The games themselves can be found at Joe's FTP. The best original game was the Thrust-deritave Oids, of which there is a beautiful Mac OSX-version by the original makers. The legendary Robotron clone Robotron-clone Llamatron, by Jeff Minter has its original and best version on the ST as well.

240px-Llamatron
Emulation is provided by Nostalgia
You need a bios though, Tos, which can be obtained (legally only if you own an ST) here,

World of stuart favourite Dr. A, reviewed the worst ST game ever here