Synergy lets you easily share your mouse and keyboard between multiple computers on your desk, and it's Free and Open Source. Just move your mouse off the edge of one computer's screen on to another. You can even share all of your clipboards. All you need is a network connection. Synergy is cross-platform (works on Windows, Mac OS X and Linux).
"MyPaint is a fast and easy open-source graphics application for digital painters. It lets you focus on the art instead of the program. You work on your canvas with minimum distractions, bringing up the interface only when you need it."
Virtual Apple ][ is a site which will take you back to the 1980's through its collection of more than 1250 game disks online. Play and enjoy old Apple ][ (Apple2) and Apple IIgs games and other disks through your Internet web browser. You will find games like Oregon Trail and Number Munchers which many of you played as kids, as well as games like Tetris, Battle Chess, Leisure Suit Larry, Choplifter, Archon II and Kings Quest.