If you have several machines lying around your “geek room” running various versions of Windows/Linux/OsX and can’t think of a good use for them. Well my desktop died, so currently just down to my laptop. However till then, and for a while before I was using this application to seamlessly integrate the machines with a single keyboard/mouse.
You can now move your mouse over to my to another screen just by going off the left edge of one computer screen to the other. (Depending on setup of course.) At which point you will have full control of the laptop and can even copy and paste between them as if they were one machine. It is also free!
Check it out.