Recycling is called upcycling theses days; ripped sheets make great rag rugs and baskets and footstools or poufs. I stuffed my poufs with old sleeping bags.
I started crocheting from the top centre with 10 single crochets. To make the pouf nice and smooth, I continued adding stitches slowly with new rounds. The rule of thumb is to add stitches only every other row and do normal single crochet every other row.
The first round of adding stitches I added two single crochets (sc) to every single crochet, and on the second round of adding stitches, I added two sc to every other sc; on the third round, I added two sc to every third sc etc. This way, as long as you crochet normal single crochet rounds in between, the added stitches will not make your work wavy. This technique I have of course learned while making baskets.
When you reach the desired diameter, stop increasing. When the pouf is high enough, start decreasing the number of stitches in each round.
Some patterns for poufs use yarn, others T-shirt yarn
This site uses T-shirt yarn http://www.gleefulthings.com/blog/?p=8688