Watching Replays

So I was wondering if there was any way to watch your replays without opening your client. When you download the replay it saves it to a file on your computer so I would think that you'd be able to but I can't figure out how. I know that when you open the client and go to match history you can watch the replays that way but I just wondered if there was a way you could just open the replay from the data saved to the Replay folder in the League of Legends folder.