Often, when I'm finished with a hard ride, the legs need to cleared. It's helpful to cool down in the last 10-15 minutes of a ride, but one of the best things I've found to help clear the legs is to lean them up against something whilst laying down apres velo. The point is to have the legs at an angle of about 30-45 degrees to horizontal such that they are above the heart.
Many of the gear heads and marginal gains wonks out there swear by the use of compression socks, but these can be expensive and don't really add value given that you can put your legs up. In such cases, I'd much rather spend my coin on stuff that wears out than duplicating what can be achieved easily with what's already on hand.