Problem: It's someone's birthday, and you want to make a sheet cake, but you can never get it out of the pan without cracking it or crumbling it in some way.
Solution: Aluminum foil. If you line the pan with aluminum foil, not only will you be able to remove it easily, you'll also have a plate-of-sorts that fits the cake perfectly.
Solution: Mine were washable markers, and baby wipes worked like a charm! I was also told make-up remover, oil-based soap, green tea soap from Trader Joe's, and baby oil for the really tough ones. Of course, you could always soak them in the bath, too, but sometimes, well, marker is tough.