Ran across these boxer briefs while looking for bamboo t-shirts and found TASC Performance.  The fabric is amazingly soft and comfortable and feels like a high quality Pima cotton, but lighter.  Unlike pure cotton, this fabric really breathes.  Also unlike other fabrics, like Capilene, it feels dry while moving moisture.  Holds its shape well. The sizing for all TASC products is generous, so don't order up.  If you want these to be snug and supportive, consider ordering a size down.  I wear these and other TASC products every day - I'm not much of an athlete, I just like the comfort.