I LOVE scrappy quilts and make more scrappy quilts than themed ones. One of my favorite and easy to make with HST's is the Depression block. It is easy because I put a light fabric against a dark fabric for the HST's, then I fill a paper bag that I can't see through and pull out the HST's randomally to make each block. Here is the pattern site.
http://www.quilterscache.com/D/DepressionBlock.html This is a free pattern and a great way to use up bunches of scraps.
Julia