I stumbled upon this bit of insanity when I was at a friend's. I was instantly hooked. Nothing is sacred to Milk and Cheese, and they don't apologize for it.
Milk is, obviously, the half-pint of milk.
Otherwise known as The Hercules of Hate. Cheese is an orange wedge of anger, AKA The Sampson of Spite. Any other characters appearing in the panels are usually in some way maimed before the start of the next one. So, there aren't really any other recurring characters. I don't think the world would survive.