Bitters/Special Bitters/ESBs are always good and easy. I am still working on tuning my recipe so I can't be awesome like yooper and give you a link to something I have tried. But you can go pretty simple with the grain bill and hop schedule and get something pretty tasty.
Just keep in mind, with whatever you brew, that the simplest recipes will be the quickest. If you have a ton of flavors competing, you'll need to wait until they meld together.