wine
WINE Is Not An Emulator - runs MS Windows programs
Wine is a program which allows running Microsoft Windows programs
(including DOS, Windows 3.x, Win32 and Win64 executables) on Unix. It consists of a
program loader which loads and executes a Microsoft Windows binary, and a
library (called Winelib) that implements Windows API calls using their Unix or
X11 equivalents. The library may also be used for porting Win32 code into
native Unix executables.
This package contains the Win64 version of Wine. You need the wine32 package
from the 32-bit repository to be able to run 32-bit applications.'
Home page: http://www.winehq.com