This is not directly related to HE, but it was a really cool-guy moment for me. I went to Sonos from the Echos due the integration with HE. Today I was settling down to watch football and it dawn on me that the Connect has an audio input. 10 minutes later, I had the TV connected to the Connect and I now I'm able to stream football audio through out the entire house (7 other Sonos devices).
Now I'm trying to figure out how to set up the API so I can use a virtual button to access the Line-in.