T-Shirt Necklace - I've heard these are easy DIYs and love the ombré and these colors.
Six Sisters' Stuff: DIY Bleach T-shirt Tutorial - (I think this would also work with fabric dye sprayed onto white or pastel colored t-shirts if you don't want to use bleach) great activity for a youth group
Or just shrink and slash it. | 14 Cute DIYs To Make An Old Band T-Shirt CoolAgain
SEWING AND FASHION TIPS: RECYCLING OF SHIRTS AND T-SHIRTS - 2. Lace insert in t shirt