Splits are easy when you're a little kid and flexibility is your friend. But joints and muscles naturally stiffen as you get older, making extreme stretching - including splits - increasingly difficult. You also get jipped of that wonderful hyperactive playtime called recess, when such physical tricks usually take place.
Lubricate your joints to do the splits once again by easing them into the move. Watch this yoga video to see how to do the Monkey pose - basically a split - slowly until you can reach the floor.