Gametrailers has many interesting retrospectives which are documentaries on your favorite games. These documentaries are interesting for any hardcore gamer and a must watch for fans of the series that ae covered.
The first couple of retrospectives were only one episode and include Prince of Persia, Daxter, Dungeons and Dragons. Silent Hill and Mario Kart.
The first retrospective to cover more then one episode is the Zelda retrospective. It covers all the Zelda games and tons of Zelda lore you may or may not have known. It also covers the Zelda timeline theories. The Zelda retrospective is 6 parts long.
Metroid was next and is only 5 episodes. The next retrospective was a whopping 13 parts the biggest so far. This covered all the Final Fantasy games. If you love Final Fantasy this is the retrospective for you. Metal Gear came out next with 5 episodes.
They made a cars of Grand Theft Auto retrospectives which was in two parts but was fairly weak compared to other retrospectives and only focused on the cars that were in the games not the games themselves.
The last one done was Star Wars. Star Wars is another long one at 10 episodes. It also covers the most time going back to the Star Wars arcade of the late 70's and even the atari games of the 80's being older then any of the other franchises covered.
War Craft has recently been started and only has one episode out so far.
Typically a epsiode last 10-20 minutes each. If you are a fan of a franchise you will love these. If you just like video games in general you will also like them and learn alot.