In one of the many Independence Day weekend sales, OnLive’s having a big sale on many indie (and several non-indie) games. You can view all of the titles on sale here.
But let’s cut to the chase; there’s only one game here you must buy.
For one of the best horror games of all time.
You should accept their gracious offer right now, and I must give thanks to OnLive for their extreme generosity and for their help in making this amazing game more easily available.