take a cold shower or ice bath. also shake your thighs to get the latic acid out, drink tons of water, and STRETCH BEFORE AND AFTER EXERCISE (MOST IMPORTANT) and continue to exercise every week. don't give up, not being able to get off the shitter been there done that but your body get used to working out and your legs/ muscles won't stiffen up anymore.
solid advice
Actually, if you read the articles posted earlier it's the opposite of solid advice. Besides the obvious encouragement to keep exercising of course