I think this is a good promo:

Rocketmiles is a third party hotel booking site. Instead of trying to provide discounted hotel rates, they provide hotels at normal rates but increased alrline miles.
Current promo is 3,000 Aeroplan bonus miles on your first booking.

So if you're booking a simple 1-night hotel stay, you can earn 4,000 Aeroplan miles quite easily.

There's also a link from Aeroplan's website here.

Credit to rewards canada blog for pointing this one out.