SN Brussels Airlines is offering a tremendous deal right now on economy tickets from Newark to Frankfurt via their Brussels hub. Many dates have already sold out, but try out different dates in October and November if you are interested. While $263 r/t is impressive, keep in mind that you can earn miles for cheaper on a well-routed domestic mileage run. But this is a great deal if you are interested in a cheap trip to Europe.
Though the flights are coded with SN Brussels flight numbers, they book on Continental and Lufthansa codeshares. Unfortunately, no non-stops on Lufthansa are available (that would allow you to use a United SWU to upgrade to business class). The fare earns 100% credit with UA, CO, and US.
I'm looking at a weekend mileage run Oct 15-17.