My biology lecturer used to constantly write 'Orgasm' instead of 'Organism'.
I'm not sure whether he did it on purpose, or he was just mildly dyslexic - when someone pointed it out he seemed genuinely surprised.

Seemed a bit odd to have teachers who can't spell at A-level though.
(Half of Stephen Fry's right buttock pissed on your dog on, Tue 22 Apr 2008, 17:11, Reply)