Here is an amazing YouTube find: It's a game between the Montreal Canadiens and Toronto Maple Leafs way back in 1933.
The rare video footage captures such legendary figures as Howie Morenz, Charlie Conacher, Aurel Joliat, Red Horner, Joe Primeau, King Clancy, Hap Day, Battleship Leduc, Frank Finnigan and many others in action.
The footage, narrated by the legendary Foster Hewitt, is 8:37 minutes long. It is a bit confusing as both teams are wearing their dark uniforms.
Note how bodychecking as we know it today is almost non-existent. It was still a physical game, but hitting along the boards is rare. Also the pace of the game impresses, given most of these players are playing most of the game. There is very little passing, and a lot of solo rush attempts. And watch the defenseman, who strictly stay back to defend.
YouTube is home to an even older set of NHL video clips. Here is footage of the 1929 Chicago Blackhawks, retrieved from an old black and white 16mm home movie reel. There is no audio.