Isn't it fun to find blogs with interesting and inspiring knitting projects?
I've been a reader of Ingrid's blog "allerleisocken ... und mehr!" for a while and she recently posted about an afghan she made using sock yarn - click here. Many times, when something is made out of sock yarn, it still looks like sock yarn, but hers is done in such a way that it goes beyond the yarn. I have a lot of sock yarn (a lot), and also a lot of Koigu which would also work.
Of course, when visiting websites, one click leads to another and I found Ulli's Blog, specifically this post from 2009 where you can see her bright and colorful afghan, plus a link to her pattern, here.
I might have to start making the occasional block as this could a good long-term project: finish a pair of socks, make a square. It would be a good travel project, too, as it's portable and easy to do. It also becomes a memory-afghan.
It'll be fun!! - Es wird Spaß machen!!