Generally, I get into work about 15 minutes late. I come in through the side door, that way Lumburgh can't see me. Then I just sort of space out for about an hour.
I just stare at my desk, but it looks like I'm working. I do that for about an hour after lunch too. I'd say in a given week only do about 15 minutes of real work.
Actually, I'm a college "admissions counselor", and do some graphic design work for my day job and on the side.