Javatari - Javatari is a multiplayer Atari 2600 emulator written in pure Java with no external libs.
Basilisk II - Basilisk II is an Open Source 68k Macintosh emulator.
Stella - Stella is a multi-platform Atari 2600 VCS emulator released under the GNU General Public License...
Sheepshaver - Home page of the SheepShaver Macintosh emulator
Mame - MAME stands for Multiple Arcade Machine Emulator.
PCE - PCE is a collection of microcomputer emulators. At the moment it contains three emulators: