Rag Rugs

I just finished crocheting a rag rug to lie in front of the bathroom sink. It took one king-sized sheet and one twin bed sheet torn into about 1 1/2" strips. I connected the srips together by cutting a small slit in the ends and looping them together the way you loop rubber bands together - running the tail through the head. If you want to see a demonstration of the technique, you can watch Rag Crochet Annie's Do-and-Learn Way video.
The pattern I had was for an oval rug. Had I followed the directions exactly, I believe I would have had too many increases at each end, giving my rug a ripple on both sides. When you are working a pattern, and you don't think it will come out the way you want, change the number of stitches until it does come out right. You can easily back up and fix things too, if you need to. That is one of the best things about crochet. It's easy to fix.
The rug is worked in double crochet with a Q hook. I worked around both sides of the starting chain for the inside and worked seven rows around after that. It's about 2 1/2' by 3' so I got a pretty decent-sized rug without investing a lot of time or energy.
The worn cotton of the sheets makes a soft, cushy rug. If you use heavier material like denim, you'll get a firmer, more sturdy rug. (Either cut narrower strips or use an S hook.)
Rag rugs are fun, versatile, colorful, washable (depending on the material), and make good use of stuff you would ordinarily throw in the trash.

I'll bet some of your friends wouldn't mind having one or two and might be persuaded to give you the shirts from the backs of their closets if you asked.

Happy crafting.