If you can, find a teacher that is willing to kiss a pig for donations. Or you can have 4 teachers volunteer and the teacher with the most money gets the opportunity.
Tell the students that if you raise a certain amount of money the teacher will kiss a live pig at the next pep assembly. At the event, sell pictures of the teacher smoochin’ the pig for a buck apiece. Students love it, and lots of staff will contribute to the funds as well.