It's being analyzed all over the baseball blogging world and the math and means of getting there are still being questioned, but this is a fun little toy. You enter the names, SLG, and OBP of 9 players and it tells you how many runs per game that line up would score. It also gives you the 20 best and 20 worst line ups with those 20 players. here is another version. It doesn't give you results that are as detailed, but it allowed you to simply click on any 9 players in the majors and click a button to see what the best line up of those 9 players would produce.
Some of the uber-statheads are taking it a bit too serious, but anyone with an interest in baseball and numbers should be able to have a little fun with it.