Steam has discreetly opened up the beta for their in-home streaming feature, sending out invites. This allows any Steam user with two computers to stream from one computer to the other.
Early impressions are mixed, as expected. Steam managed to set it up so that some users could get it up and running painlessly, while others are reporting issues to Steam for the 1st time. Performance also varies for individual games. Still, other people are able to stream their desktop as is. It should be interesting to see how long before the beta goes public.