Need Speech Ideas!

I have to give a speech tomor­row that
1) lends itself to visu­al aids (I have to have three dif­fer­ent types, one of which uses the over­head projector)
2) is some­thing a group of col­lege kids “need to know”
3) does­n’t offend the crotch­ety, con­ser­v­a­tive, “Coach” pro­fes­sor so much that he gives me a bad grade.

Ideas? PLEASE?