Legend has it if you press "F" during this boss battle it accelerates you to the point where you can pass the Yeti. While it definitely does accelerate you, I cannot personally confirm that you can actually beat the Yeti but that is what they say. That is what this comic refers to. Update: I have outrun 'em for quite some time but never reached any kind of "end". :)
So, make your very own 'F' key pendant symbolizing...anything, really. Cheating death. Overcoming obstacles in life. Your 1337 gaming skillz. Undying affection, maybe? Whatever.
Some may say "Congratulations on drilling a hole in an F key." To which I say, Bah humbug! There is elegance in simplicity. Any designer worth his/her salt will tell you that complexity does not a good design make. Besides, half the fun is that it doesn't look like much to write home about unless you know about SkiFree/the comic.
(If you want to learn more about the game, or download it (runs in windows and works fine in wine), please see http://ski.ihoc.net/. If that doesn't work, try the google cached version. Legal downloads, yay!)
Step 1: Materials & Tools
An 'F' key (duh).
Cord/wire to string it on (I used SoftTouch nylon beading wire).
Source of fire (I just lit a candle).
Small-diameter, sharp-tipped metal implement (I used a special xacto attachment).
Crimping pliers (I mislaid mine so I just used regular small pliers. It works, but be warned it's a bit trickier and you don't quite get the nice crimp you do from using the specialized pliers.)
Step 2: Putting It All Together
Try to get the holes as exact as you can if you're using a string that doesn't have a lot of slack in it (the nylon wire has more "give" room when it hangs so it doesn't matter as much).
Thread the string through both holes. Then attach your clasp. If you're using crimping beads, put those on first, then the crimp, then thread the string back through the bead and crimp as shown in the pictures.
Be forewarned that few will know why on Terra you would have such a thing, they will assume it's an inside joke or maybe your name is Fred. Take courage; wear your xkcdian SkiFree 'F' pendant proudly, knowing that you have reached a level of esoteric few ever will ;-> !