Project! Nintendo pixel tees
Check out this awesome geek chic, retro-gaming, Nintendo pixel t-shirt. Cool, right? The best part is that you don't have to pay through the nose at your local hipster boutique to get one. You can actually make it yourself for the cost of a plain t-shirt and some craft supplies.
So I say: why not kill two birds with one stone and turn this into an after school project? You'll need a shirt to make your stencil on, poster board, masking tape, painting sponge (or paintbrush), washable fabric-safe marker, acrylic paint (or fabric paint), ruler, and an Xacto knife.
The website with the full instructions seems to be having some kind of technical difficulties, but this post on Crafty Crafty will at least get your started until the step-by-step set is up and running again.