McDonalds Germany, which according to a guy who works in their German HQ is the national franchise that has the most "special burgers" promotions per year of any country McDonalds is active in worldwide, currently has a "Shrimp Lemon" burger and a burger called the "Beef Sizialiana".

The Shrimp Lemon includes a battered shrimp patty on an herb bun with salad and a special lemon-garlic sauce.

The Beef Siziliana has a beef patty with black olives and sun-dried tomatoes worked into the patty on a Ciabatta bun with salad and onions.

Pictures here: http://mcdonalds.de/html.php?&nt=Produkte

Haven't tried them yet, but I hear the Shrimp Lemon is actually pretty tasty.