Through the end of the year, Air Canada is offering bonus points for flights to and from certain cities in North America and around the world. Registration required.
They give an example of a roundtrip from Edmonton to London Heathrow and back, you get 500 points each for your departure and arrival at Edmonton and 1500 points apiece for arriving at and then departing from Heathrow, for a total of 4000 bonus miles on the one trip.
The bonus is available for takeoffs and landings at the 31 airports listed above, and can be earned repeatedly and on most fares:
[F]or travel between Canada and the U.S. or within Canada: Tango (N,G,P,E,A), Tango Plus (M,U,H,Q,V,W,S,K,L,T), Latitude (Y,B), Executive Class Lowest (D.Z), Executive Class Flexible (J,C) and for international travel: Tango (K,L,T, N,G,P,E,A), Tango Plus (M,U,H,Q,V,W,S), Latitude (Y,B), Executive First Lowest (C,D,Z), Executive First Flexible (J).