My alarm went off 40 minutes late, and I didn't have time to make myself look good before class, so that's why I was looking so unfashionable in my gross sneakers, sweatpants, and frizzy hair.

Me: "I can't make your Econ final - I'm having an emergency appendectomy. When can I make it up?"

Prof: "You can't. I'll have to give you an 'Incomplete.' Maybe I can give it to you next quarter. I strongly suggest you take the final at the scheduled time."

Me: "Is there something about 'emergency appendectomy' that you do not understand?"

You have an assistant? Lucky, lucky!
My excuse is that I don't have one.

Yeah, what's with the assistant? No man is a hero to his valet, and all that. What do you do with this person? Are you allowed to fuck them up emotionally, like all those Beverly Hills people we read about? Can you severely chastise them for bungled orders of Chinese food? Do they pick up your Martinizing?

My assistant is much more well-adjusted than I am, so I try to be as nice to her as possible, in hopes that she'll stick around a while and some of her sanity will rub off on me.

Best excuse I ever heard occurred in grade school. One student said, "Yes, I did my homework, but I lost it in a fight with a guy that said you were a lousy teacher!"

The emergency appendectomy is a good one. Of course, some of the dimbulbs who ended up flunking out of college overused it. The teachers were asking, "Just how many appendices do you have???"

I work with a very troubled person who seems to have a flood at his house about once every six months.

Just watched Will and Grace with mom and your assistant reminds me of Karen Walker.
A lame excuse would be: "I just overslept and had to bring my child to school." but they have no child.

You know, people think it's weird, but I always just tell the truth:

I was too lazy to get up when my alarm clock went off, sorry.

I was stupid, I stayed up into 3am watching star wars.

I just didn't want to come in, it took me some time to convince myself that I had no choice.

People accept these. I've got no idea why. They never call me on the fact that it's incredibly immature to admit to doing stupid stuff like that.