This is a great bonus mile offer for hotel stays as it awards you on a per night basis rather then the standard per stay basis. Also, we could not see a maximum number of nights restriction so technically speaking you can earn this bonus many times over until it ends on May 31. The offer is as follows: (as pulled from our Aeroplan page)
Earn up to 1,000 Bonus Aeroplan Miles per night for stays at participating Fairmont Hotels Worldwide.
– Earn 500 Bonus Aeroplan Miles PER NIGHT for eligible stays in a standard room.
– Earn 1,000 Bonus Aeroplan Miles PER NIGHT when you book our GOLD FLOOR or a SUITE at participating Fairmont locations