Bernat has just come out with a line of glow-in-the-dark yarn (link) . It is only available for a limitied time and can be purchased at Micheals.
I am going to buy some to knit a hoodie with a glow-in-the-dark Transformer logo. However if you don't have a child who is interested in Transfomers, Bernat has provided free downloadable patterns for a glow-in-the-dark trick-or-treat bag, ghosts, alien head bands, and more.
What are you going to do with your stash of glow in the dark yarn?