'average' of www.averagegames.com has created a cool little Silverlight bridge builder game using the Farseer Physics Engine.
From the game site:
Bridge Breaker
Design a bridge and then destroy it! Bridge Breaker is powered by a realistic physics engine to provide an unparalleled level of ultra-super realistic bridge destruction.
Check it out here: http://www.averagegames.com/games/bridgebreaker/