Jumping into an ice bath after a long run, hill workout, or set of sprints sounds like torture but it only feels like torture. Those activities will break down the best of us and the one sure thing that will give you faster recovery to get back out there for another solid workout is a 4lb bag of ice and a nice cold bath.
By the way, don't try this if you have a bad heart. You might die from the shock. Seriously. ;)