I just found a really helpful tool while I was browsing on Crochetville.
Check out this random stripe making tool.
It was designed with knitters in mind. But the uses are endless.
Currently I am crocheting a baby afghan and I've been adding a stripe here and there but I found that it wasn't as random looking as I wanted. This tool will let you preview your color choices and fiddle with the pattern until you get it just right. Check it out.