I adore this summer braid scarf made from t-shirt material. Check out the instructions for three different versions of it here from Pickles. There are tons of other fun projects there too, but some appear to require much more than an old t-shirt...you know, things like talent and patience. Truly amazing projects though!
Also, check out the blog Dollar Store Crafts (where I found this scarf) for more awesome projects.
My project to-do list is getting really long...can't wait to get home and get started!