The game of Go has been around for thousands of years and is still one of the world's most popular board games. Try it out and decide for yourself whether it's really That Good.
I recommend starting with a shortened (but otherwise completely authentic) version called First Capture Go. Shortening the game bypasses some rules and situations that can be confusing to first-timers. That way you can focus on the basic concepts and cycle quickly through several games.
Here's a PDF with everything you and a friend need to play: First Capture Go
Regional Go websites -- USGo.org ... OregonGo.org ... PortlandGo.org
Play Go online now -- gokgs.com
Go on Wikipedia -- http://en.wikipedia.org/wiki/Go_(game)