These are the ones I went for, mostly because they light up. Festified makes a dog sweater, a women's sweater dress, and a men's/unisex sweater, and they're all hilarious.

Press to rework the latter's famous "Shaggy Dog" sweater—and the results are really damn cool. The Shaggy Dog is an institution, counting men like Cary Grant and JFK among its fans over the years.