i had at least 2 very weird teachers (and several others who were quite odd but don't quite qualify)
a sex obsessed Biology teacher:

i'm convinced he took up the subject just to study the sex lives of various critters, although he had a particular fascination with the sex lives of plants. Just the look of glee in his eye when he talked about anything sexual was enough to convince anyone he was slightly perverted. He would also throw in as many inuendos into lessons as he could manage. He often wore lycra trousers to teach lessons through which you could see his genitalia. The most memorable ocasion however was one lesson during my A-level course when we were studying DNA replication. He demonstrated how DNA splits in two by jumping up on the front desk and unzipping his fly several times just so if we hadn't caught a glimpse of his underwear the first time we'd all know by the tenth time that he was wearing Y-fronts. He repeated this trick several times throughout the year whenever DNA was mentioned.

#2: the muli-millionarie classics teacher

He's at least 50, quite obese and rode a motorcycle (thankfully noone i know of saw him in his leathers). He still lives with his mother, made an absolute fortune on the stock market and yet still continues to teach for fun and he would sometimes sleep in his office. He also kept an alarming amount of books about greek and roman pornography in his classroom. He hung his keys on a small statue of a man with a ridiculously elongated erection. He had another clockwork statue that would fornicate if wound up, not to mention the two sheep he kept on top the board in varing sexual positions.
If anyone asked to go to the toilet in his lessons he'd offer them a "mr squeezy" ie. a rubber band to put around their dick. If i had my yearbook here i could give you some of his less sexual quotes (the pure filthy ones weren't allowed to be published). One which i remember went along the lines of "a woman is like a motorcycle boys, you have to give her a good kick to get her started."

Oh, and also a mention to the head of geography who used to hire his geography technicians on the basis of how female and attractive they were. Well that was until one of them achieved school-wide fame via an internet porn site and shagged half of the sixth form.
( asparagus time Is in Brazil., Sun 13 Nov 2005, 20:57, closed)