I've come across a great way to greatly enhance your sock yarn stash--the "Sock Yarn Knitting Exchange." (But it's also open to crocheters.)
First, you receive a letter with two names and addresses on it. You send a 100 gr. ball of sock yarn (or two 50-gr. balls--enough to make one pair of socks) to the first person. Then you send out a new copy of the letter to six knitting (or crocheting) friends with the first name and address removed, the second name and address in first place, and your name and address in second place.
In short order, you should receive enough yarn to make 36 pairs of socks! Cool, huh? And just as much fun will be seeing who, and where, the yarn comes from.
Now, I know these things often don't pan out exactly as expected. Somewhere along the line, someone usually drops the ball. (Of yarn.) But I figure if you even receive only one ball of sock yarn, you've broken even. Anything more than that is a bonus.
As it happens, though, I don't know a lot of knitters here. So I'm throwing this open to all of you in yarn cyberspace. If any of you would like to participate in this sock yarn exchange, please e-mail me at firstname.lastname@example.org and I'll get your address and send you the info. BTW, this is only open to those in the US and Canada, because of the difficulties of mailing elsewhere.
Hope to see lots of you participate!