Fashion colored/scented breath, farts, and sweat
Create a material (solid, liquid, gas) which will react with human exhaled breath, sweat, and even farts that adds color and/or pleasant smell. Market to teenagers first. Imagine Jessica and Jennifer meeting at a school in the morning, each asking "what breath do you have today?" "Look, I have the new Passion Pink" (girl exhales a visible, pink, sweet smelling temporary puff of air) "Cool!" Now for the boys..."Jason, check out my new diesel fart!" (RRrrrippp) "Wicked! It's black!"
Reward: First samples of Florescent Green breath blasts.