During a school fundraiser for African children, I promised my 3rd hour class that I would allow them to dye/shave my hair if they raised $100 dollars. They ended up raising $98.22, so I thought I was off the hook.
Unfortunately for me, the teacher who counts all the money knew about the bet, and added the last few dollars, just so she laugh about what the students did to me.
We ended up dying my hair black during class, and then I let them rinse it out by throwing buckets of water at me during lunch. I forgot to get pictures of the actual process, but I know my students took plenty.