From now until Friday, Big FIsh Games is offering full PC and Mac versions of four of their games-- Azada, Hidden Expedition: Everest, Fairway Solitaire, and Spa Mania-- for the bargain price of zero.
I played through Azada a while back and was underwhelmed-- I kept waiting in vain for it to impress me. Fairway Solitaire, on the other hand, I've come close to purchasing on a number of occasions. Lots of people I respect have said great things about it, and I was sad when the clock on the demo version expired. So I urge you to grab the free download while it lasts.
Details here. Make sure to follow the instructions-- you have to apply the coupon code to have the price reduced to zero.