1.
The Higgs-Boson told me not to.
2.
My Xbox was broken and I had to spend all day fixing it!
3.
The zombies kept me awake all night.
4.
I was reading about goat spiders and I got so creeped out I couldn't leave my house. Goat spiders, man!
5.
I was abducted by aliens. They probed me.
6.
I had explosive diarrhea.
7.
Why'd I miss the exam? Well you see...QUICK LOOK A SQUIRREL!
8.
Look, it's hard to make it to these exams AND keep Gotham safe.
9.
I was having a conjoined twin removed.
10.
I was kidnapped by the CIA.
11.
My psychic adviser advised against it. Psychically.
12.
The confluence of the numbers on the test, when completed incorrectly, formed a mystic conundrum. I couldn't risk the release of the Great Old Ones by the taking of this test.
13.
But, there was a My Little Pony marathon!
14.
Why bother? The world's going to end in December 2012 anyway...
15.
I am not the person you are looking for. I am a clone. I cannot be held responsible for the original's actions.
16.
I was having a deep philosophical discussion with Benjamin Franklin's ghost.
17.
Ninjas attacked me on the way to class.
18.
It's *really* hot outside.
19.
My D&D group had a special session and I just couldn't miss it! We were going to hit 10th level!
20.
I was turned into a newt by a witch. Well, I got better!
21.
Two words: Guild. Raid.