OK, admittedly, this was so easy it doesn't remotely count as bad ass.
I was biking home yesterday, and my shifter stopped working. I've got an 8 year old Gary Fisher Mako. Basically, one of the levers on the trigger shifter wasn't catching at all. I figured I needed a new shifter, which would probably also mean replacing the cable. Doable, but I've never done it before, so I figured I'd spend a couple hours on Saturday learning how to do it, and make do with 1 front gear in the meantime. Fortunately, I googled it. Turns out I just needed to clean out the shifter. I didn't even open it.
1) Spray in WD-40.
2) Click through the gears to work it around.
3) Wipe it off.
4) Spray in lube (I used Triflow).
5) Click through the gears to work it around.
6) Wipe it off.
Took about 5 minutes while my oatmeal was soaking this morning.