.rar is a compression type file that made by WinRar. So, you will need WinRar to open it. You can get it from net. There are many sites that provide it, including it's official website www.winrar.com. There are also many compression type file, such as .zip, .sit, .ace, .gzip, and other. To open it, you must also have it's own program. But i say some program can handle many types.. . The only thing that i don't understand is, WHY we do not make an universal compression type so we can easy use it. . . An economic game, though...