If you're in an area where this works, it's super cool.
https://www.aereo.com/
We don't have it in Seattle yet, but I signed up on their list to show Interest and have asked other people to do the same.
They basically put a board with hundreds of little HD antennas into a datacenter in town where they get good signal, and then transmit the broadcast signal over the net.
The cable companies have been trying to shut them down, but since each subscriber is using a single tuner and antenna, just located remotely, they haven't succeeded in doing that.