Want to turn one computer into two? If you’re running Linux and have a box that can support two monitors, you can do it for free with a two-user license of Desktop Multiplier. Once installed, the program lets two users access simultaneously, with what the developer says are only minor performance hits (though we imagine that it might be a little tougher if both users are running graphics or processor-intensive apps). The developer, UserFul, also offers a commercial version of the program that can handle up to 10 users on a single PC. Of course, this only works with Linux; if you want to do something similar with a Windows box, you may have to spend about $200 for something like the Applica U2 Lite, a “reverse KVM” that installs in a PCI slot. Or you can always spend another $100 and get an ultra-cheap PC.