Virtual Machines
VMware Player
With this you can use virtual machines of Windows, Linux and a few other OSes to play games, old games, test software, surf the web safely and more. You can not create a VM though, but there are free virutal machines already out there made for several flavors of Linux. Do you have an old game that doesn't run correctly in anything but Windows 3.x or Windows 9x? This is a good solution for that.
VMware Server
This allows you to create a VM that can be used in VMware Player. You can also run multiple virutal machines. So if you need a Windows virtual machine made, you'll have to use this.
