Stealing this word for word from Pers, cos it's pretty darn spiffy keen. Sure, the chances of someone being able to legitimately call them on it are pretty slim, but the concept's nifty as all heck.
Travelodge is awesome! They're offering a free night's stay for any married couples with the names Mary and Joseph. They say, "The 'gift' of a free night's stay is to make up for the hotel industry not having any rooms left on Christmas Eve over 2000 years ago when the original 'Mary and Joseph' had to settle for the night in a stable."
http://www.travelodge.co.uk/whats_new/#mary_joseph