A shirt that never needs washing?
 

For Christmas I got a Pearl Izumi X-Sensor T shirt from www.wiggle.co.uk. It's intended as a base layer for activities which make you hot. In addition to all the usual moisture-wicking and quick-drying cleverness, it claims to be made of "X-Static silver based antimicrobial fiber [which] naturally deters odor-causing bacteria." Plus, the "thermal conductivity of silver regulates the temperature throughout the garment." Well I've been wearing it for 5 days, with and without deodorant, and it makes sweat patches disappear as if by magic, and still doesn't smell. Plus it weighs almost nothing and packs down to naff-all. I'm very impressed. But it does cost 40 quid. I have read that Salomon also make clothes from this X-Static fibre.