What are your guys' best trail fix tips? Share 'em here!  

LONG LIVE ZIP TIES and DUCT TAPE, they can fix anything!!!!!  

this may seem odd but i always carry extra valve stems for the tires. I actually lost one once while uising a tire deflator that removed the valve to lower the psi. i didn't read the directions first, however, and when i removed the deflator the stem shot off in  to the woods and was no where to be found. I used a valve cap on the valve stem-less tire/rim for most of the day but had to replensih air every hour. At the end of the day i finally stopped and bought a valve stem from a nearby tire shop.

by the way: DUMB GUY tip of the day; if you are too lazy to swap on your spare tire after misplacing a valve stem that results in a flat tire at least consider pulling the valve stem from the spare tire and installing it in the tire/wheel that you lost the stem from and re-airing up. it is much easier than changing a tire and you won't feel like an idiot after someone else on the trail points out this option.  

Ive used a small elect air compressor a couple of times for veh that lost fuel pumps and vapor locked.I tapped into the fuel tank vent line.