Or, if you'd just like to re-inject some flair into an old pair of your favorites, Argentinian design group JeansMakers will create you a one of a kind masterpiece from your oldies.
Patagonia has extended their line of recycled soda-bottle fabric to include not just fleeces, but also rugged performance pants. These Extension Cord pants look up for anything.
To make sure those new pants don't get chewed up by your bike chains, slap on a pair of Reflexite Trouserbands. With built in reflectors, you won't get chewed up by cars either.
And, as with all treehugging habits, it's best to start young. So swaddle your little ones in Speeses organic cotton pants -- and shirts, hats, and jumpers.