The sorest I've ever been was probably the day after I was involved in a collision at home plate . . . during a Whiffleball game (serving as home plate in this case was a lawn chair).  I sprang up limping and cursing the guy who had tagged me out, but I can see now that I may have been playing with more intensity than is called for in backyard sports.

Also, because it's going to drive me crazy if I don't mention it: there seems to be some inconsistency, even on the official site, when it comes to capitalizing the game's name and spelling it with or without the letter "h."