This app was mentioned in 3 comments, with an average of 1.33 upvotes
"What you can do with it" depends on what apps you can find, but to answer your question, yes: There are a lot of "virtual theater" apps that are cardboard-compatible.
If you want a quick (and free) demonstration of the concept that's still high quality I recommend you check out the OpenMovieVR app. Unfortunately you are only able to watch movies from the Blender Foundation on this app however the "virtual living room" environment is very nice and it will let you get used to gaze controls and other cardboard-basics (also a couple of the movies are fairly decent even if they're short).
If you want the freedom to watch your OWN videos then personally I like CMoar Cinema. Some people don't like it because of the drift but I like the movie theater environment plus I like how you can play either locally stored videos, videos on your LAN, videos from a PLEX server, or even Youtube. (Quick Note: The free demo app is just for testing to make sure the app performs ok on your phone - there's a big ugly watermark that makes the screen unwatchable until you pay for the full app)
Those are far from your only options - there's TONS of virtual theaters for watching movies, just search the Play Store.
It's a Google Cardboard app available in the Play store.
https://play.google.com/store/apps/details?id=com.blendfx.omvr
Edit: I stand corrected... It is available on the Oculus store for the Note 4 - to be honest, I didn't check there first - went to the YouTube video description, which linked to this page: http://blendfx.com/openmovievr/
No mention of GearVR or Oculus versions on that page as of 4:43 PM July 20, 2016... A very prominent link to the Play store version though. Guess it hasn't been updated yet.
the closest thing that might actually seem cool but it only has the Blender foundation films.
https://play.google.com/store/apps/details?id=com.blendfx.omvr