Well, it's not exactly the 150th anniversary of the war itself, we're a few months away from the start of the bloodshed, but 150 years ago this week the election of Abraham Lincoln marked the events that proximately led to the outbreak of the war.
There are already a number of interesting sites marking the various 150s coming up, although this one is already establishing itself as one of the best.
Of all the wars associated with the hobby of board wargaming, none, perhaps, is more closely linked to the hobby than the American Civil War. It was the approaching centennial of that war that inspired the father of wargaming, Charles Roberts, to take the ground-breaking system he had used in his hypothetical first effort, Tactics, and apply it to a historical situation -- in this case the Battle of Gettysburg.
The sales success of that title (deeply flawed as the game was) that really launched Avalon Hill and the wargame hobby. It's always been true that history-based wargames have been much more popular than fictional ones. Gettysburg was followed by a whole series of historical wargames by AH, including several on the Civil War.
So it's deeply fitting that Hasbro is re-releasing a 150th Anniversary edition of Battle Cry this month, which could, maybe, introduce some new players to the joys of history-based board wargaming.