The team from Draknek have, for the first two weeks after today's release, made their game, A Good Snowman is Hard to Build, available for "pay what the temperature is". This deal will work if you purchase directly from their site, agoodsnowman.com.
This is how it works: just before having his tea every day, the monster goes out to the weather station in London to check the day's temperature. He sets the price accordingly: so if the temperature is 8°C, the game will be priced at $8 for the next 24 hours. It's a great idea, which ties in amusingly with the subject matter of the game, but is also clever marketing by Draknek. Keep an eye out on the site for a review of the game soon.
It's also worth knowing that It'll also be available on Steam for a fixed 20% off the normal price of $12.
Here's an up-to-date forecast for the next five days which might help you find the best deal.