Synergy-Foss is a small little piece of software that runs in the background that lets you slide your mouse (and keyboard) focus to a different computer on the network. Yes really! Set it up on 2 computers next to one another and you can control the other computer from one keyboard/mouse.
Unfortunately, you can’t slide a window on to the other computer!
The version of Synergy I am using has some problems. It crashes sometimes if you play with the settings. It also does not allow the screens to lock, even after you quit it. Hopefully they’ll fix these little annoyances. This could be a great little tool.