There are several varieties of stretches you can do. luger0 explained several of them. Here are a couple more that have worked for me:
Leg extentions: Put both feet forward approx. 4 inches apart while sitting on the ground. Keep your feet parallel and reach for your toes. wrap your fingertips around your toes, and walk your fingers down your foot. Keep doing this as an after-workout stretch until your wrist is at toe level. At that point it becomes a maintenance workout.
Modified Splits: Spread your legs as far out in both directions as you can while seated in the same position as the butterfly stretch. Scoot forward several inches while digging your heels into the ground. This forces the truck forward stretching the tendons on the inside of the pelvis, also, as you become more adept at this begin pressing your elbows into the ground in front of you to further loosen the pelvis. Also, stretch left and right cupping the ball o fyour right foot with your right hand, and vice versa with the left, this stretches the lateral muscles as well as further stretches the backs of the upper/lower legs. This is another post workout stretch. Butterfly is a great pre-workout stretch of similar effect.
Chinese Splits: Instead of stretching left and right, you stretch front and back. Slide one leg forward, the other backwards. Hold youself up above the ground with both arms, one on either side of your front leg. Your shin, and your calf should be on the ground, as well as your arms holding you up. This is a pre-workout stretch. To perform the post-workout version, slowly lower your body down onto the front and back of your respective thighs. Lower yourself only until it hurts, anymore and you risk tearing something. Both versions stretch the front/back/outside of the thigh.
These are just a few additions to what has already been brought up. Be careful trying any new streches and good luck man!
Sig courtesy of that photo-matic magician limba
I went out the way that I fight. I went out on my shield. Thatís it. Done. --Chuck Liddell
My goal is to end my opponent --Carlos Condit