I think of you started a stockinette stitch afghan, something else would freeze over before you finished. If you didn't die of boredom first! :teehee:
An afghan made with different squares is a perfect opportunity to try out new stitches and end up with something fun and unique. A big advantage is that it's so much more portable, too. Having a big afghan in your lap all through the summer would be uncomfortable to say the least.
Google stitch patterns or find a stitch pattern book for a look at what's out there.
www.knittingpatterncentral.com is a good source as is www.ravelry.com