So, what can be done with an old t-shirt, other than make it into a cleaning rags? There are thousands of things out there, use your creativity (or google). Here are a few idea's to get you started.
I saw a shag t-shirt rug for sale that someone else had made and thought "I can do that!" So I did. Let me tell you, this wasn't a fast project. I dyed the t-shirts, cut them into strips and sewed them onto a larger piece of t-shirt. It was a very time consuming process, but I do love the way it looks and I am glad that I had the patience to stick with it. And every time look at it, I will have the satisfaction that a) I made it, and b) it is made of up-cycled t-shirts.
And it is quite comfy to stand on too!