Xfinity 3D - Comcast's 3D offering - has much of the same programming as 3net.  There are documentaries and 3D movies, and sporting events to watch. 

There's one thing that Xfinity 3D has that 3net hasn't mentioned though - concerts.  The first aired on the 20th and featured the award winning rock band Kings of Leon.  More bands are planned for the future, but Comcast hasn't specified just who.