I re-purposed a bunch T-shirts into a large blanket for Aaron's birthday and a small blanket for Andrew's half birthday, both coming up in June.
I simply cut out large squares, all the same size, from the front and back of all of the T-shirts and sewed them together quilt block style. I really like how bright and cheerful Aaron's color-block blanket turned out. This is a great project to turn unneeded items into something really useful.
For these blankets, I made both the front and back T-shirt blocks. But when I was in college I recycled the high school T-shirts that I no longer wanted to wear but didn't want to completely get rid of into a quilt that had the T-shirts with designs on the front, quilt batting in the middle, and strips of old blue jeans for the back. This quilt was warmer and sturdier of course. This was also a good way to actually use some sentimental T-shirts a little longer.