Go is possibly the oldest popular board game in existence. Its history tracks back roughly 4000 years, and there are currently tens of millions of players, though mostly in Eastern Asia.

Go is a very strategic game, in which aesthetic values also play a big part. It is also extremely addictive, so it is recommended that you don't follow these links:

• A very nice introduction to the game from kuro5hin.
• Learn to play go interactively. Saman saa myös suomeksi.
• Sensei's library - A Wiki about Go.
• Go, an addictive game - Perhaps the most comprehensive resource about the game in English.
• Play Go on the Internet with Kiseido, or IGS.
• Go entry at Wikipedia. As at 24/7, it is pretty comprehensive IMHO