Headset covers
 

This is almost too simple, but it might be a good hint for somebody

I was cleaning and greasing my headset today and noticed that water and road peepee could get into the headset quite easily.

I took two slices of tire inner-tube cut the round-way like a doughnut and put them around the upper and lower bearings where moisture could get in.

If you want something more fancy, Lizard skins makes headset covers.

Mike, we used to do this years ago when we had a university mountain biking club :). The downside is that any water that DOES get in, can't get out again :( . This is why lizard skins are better, you can whip 'em off after a ride to let it all dry out a bit.

Another think we used to do to protect chainstays from chainwhip on very rough terrain is to cut a slice from an old tube the other way so you get a long narrow strip and wrap it along the chainstay, securing it with zip ties and each end. Again, I would'nt recommend this in wet climates.