Have you heard of Microsoft's Garage projects? They're side projects done by Microsoft employees during their free time, and Microsoft hosts their downloads online.
If you use several computers in the same room (or, say, your laptop and your desktop), Microsoft's Truong Do has a cool program to increase your efficiency. It's called Mouse Without Borders, and with this program installed on each machine, you can use one mouse and keyboard to control up to four computers.
It doesn't just eliminate switching back-and-forth to each machine. With Mouse Without Borders you can even copy text from one computer and paste it in another, or drag and drop files from one computer to another.
Being a Microsoft-hosted download, this is limited to Windows users. To install Mouse Without Borders, click the blue link below, then download and run the install program on each of your machines. You'll then be prompted to configure the program to your specifications.