Symless Synergy is a solution which allows keyboard/mouse sharing across multiple computers; imagine having two laptops and a desktop on your desk, but only one keyboard/mouse. It's wonderful to not have to move from one keyboard/mouse to another, and have only one on a desk instead of several.

I love being able to copy and paste text and even files between two completely separate computers without any manual action. Symless Synergy makes it seem like you are using one computer the whole time.