Synergy
Likely the single best piece of code written for the true computer enthusiast. This is a person I define as having multiple machines, running different operating systems.
Synergy will allow you to have a virtual KVM switch, that is, to switch between monitors with a click. Meaning you can use one keyboard and one mouse to use multiple machines at the same time. You simple click the representative box and poof that is the machine you are working with, you can cut and paste from one machine to another.
A little confusing, so here is a video for clarity! This is awesome!