What is the Oldest Known Board Game that we still Play?

There are many board games still in existence that were invented hundreds or even thousands of years ago. The important part of the question posed is "that we still play today".

Senet is generally accepted as the oldest board game in existence: it has been found in tombs dating from 3500 BC and 3000 BC, which would make it over 5,000 years old! The Egyptians played this racing game - that is, to win, the player must be the first to have his pieces complete their course along the thirty-squared board. Of course, the actual rules are disputable, since no one has found instructions, but Senet boards are manufactured today.

It may be that Senet is the oldest board game, but it's not the oldest still played. "Still" played today implies that people never stopped playing it, which is not the case for the Egyptian race game. It has had a rebirth since its discovery, which is a different matter.

The oldest board game that has never ceased to be played is either chess or backgammon. These two games are so old that no one really has a clue where they were invented, although several theories are postulated based on discoveries of ancient sets of similar form.

The Western world's version of chess has only really been in existence for a few hundred years, but its predecessors appeared as early as the sixth century in India, from whence it was taken to Persia and the rules were adapted and advanced.

Similarly, backgammon is documented in the sixth or seventh century. However, its predessors run much farther back than chess, with the earliest similar board being one found in Burnt City, Iran and dated around 3000 BC. That puts it right up there as Senet's little brother, assuming the historians are correct.

Another very old board game is Go. This has been played in China for over 2,500 years and bears mentioning because there has been little change in the game since the Tang Dynasty in the sixth to ninth centuries. As far as unchanged games go, it may be the oldest in the world.

Addendum

As you can see from the comments, draughts (or checkers for the Americans) is also very old. It's difficult to find any definitive information on its age, though, so it has not been included. However, it should still be considered amongst the oldest board games we still play.