I saw this pattern for a rug woven with loops from t-shirts using a Hula Hoop for a loom on Family Fun Magazine online. But I did not have a hoop. However, while visiting my Iowa grandchildren, I spied a broken hoop on their porch and asked for it (it was kind of lozenge-shaped instead of round). Last month I cut up some t-shirts and tried out the pattern. Mt first attempts were a mess--the warp loops kept falling off and were very skewed. Then I broke/bent the hoop some more to kind of get a hexagon shape and found a kid-sized t-shirt to use for the warp. That worked. My rug is not big--12"-13" in diameter--but not bad. I probably need the giant Hula Hoop to go bigger.
The Rug in progress
The finished rug
There was also a pattern for a bowl made on an embroidery hoop frame with loops cut from the sleeves. After enough rounds for a base, the weft loops are pulled very tight and eventually a bowl shape is formed: