https://www.thespherevegas.com/
Apart from the U2 shows, in October it will begin showing a Darren Aronofsky show, "Postcard from Earth".
I'm guessing inside will be something like a Planetarium, except with LED screens instead of a projector. We'll probably check out one of the shows in October.
This past weekend we decided to check out the view of the Sphere from the High Roller, which was pretty cool. The evening display was kinda like a glorified screensaver but still awesome to see.