A bit limited (tends to focus on children's shows and the early days; don't expect anything related to the long-running Hockey Night in Canada),. but it's free, and a nice bit of nostalgia so if you're in the area you might as well stop in. As another reviewer noted, don't overlook the somewhat hidden second exhibit down the escalator.
I'm not sure what it's called, but both times I've been in the building, I've passed books for sale in the lobby. Not part of the museum per se but a decent (for a lobby) selection at low prices. If I ever figure out the name for the book area I'll give that 4 stars.