Choice Hotels (Comfort, Sleep, etc) -- http://www.choicehotels.com/ -- has brought back their promo where you get at least 5000 bonus points, to bring your total up to at least 6000 points, for every two stays, which works out to enough for a free stay after just two stays. And since it's through points, it's not nearly as restricted as, say, Hyatt's program (where you get vouchers that expire quickly and come with a zillion restrictions and only work in certain cities), but of course the rooms aren't as fancy . And if you end up not wanting any free nights there, no problem, since 5000 points can be redeemed for 1000 miles with several airlines (or 2.0 Southwest credits), and so with 10 such stays you'll get 6000 miles (or 12.0 credits) if you choose to transfer instead of taking 5 free nights, and thus be earning an average of 600 miles per stay.

Other chains have other promos which may work better for you depending on what kind of free nights you want where or what kind of miles you're collecting, but with the other programs it's much harder to generalize, because they have such a wider range of factors.