There is a Reddit forum called TheMakingOfGames that specializes in behind the scenes and 'making of' content:
http://www.reddit.com/r/TheMakingOfGames/There's an
alphabetical index of all the submissions.
Some notable videos include:
Long videos:The Art of Playing - PBS show segment on game development, including footage with developers Tiger Style (creators of Spider: The Secret of Bryce Manor), Davey Wreden (The Stanley Parable), and Certain Affinity (Halo series multiplayer) (27 min)
titled Grounded (1.5 hr)
- An excerpt from Double Fine's making of documentary of their newest Kickstarter funded adventure title. (24 min)
Metal Gear Solid 4: Hideo Kojima's Gene In Japanese audio, click the CC button for English subtitles. Inside look at Konami's offices and footage during development of MGS 4. (36 min)
Turtle Rock Studios - History of the developer behind Left 4 Dead and upcoming game Evolve. (27 min)
EverQuest - EverCracked! documentary by Jace Hall on SOE's first MMO with interviews and anecdotes from developers. (48 min)
Short videos:Metal Gear Solid 5: Ground Zeroes - Stylish behind the scenes video dissecting the components that go into rendering the final image
The Divison - Behind the scenes at Massive Entertainment with their Snowdrop Engine for their upcoming PS4/XB1/PC gen title.
Hearthstone: Heroes of Warcraft - Behind the scenes of Blizzard's digital card game, which incidentally uses the Unity engine.
Text articles:Crash Bandicoot making of article by Andy Gavin, former lead programmer and co-founder of Naughty Dog.
Dark Souls - From Design Works book about the design and look of environments, enemies and characters and interviewing director Hidetaka Miyazaki and four artists.
Dirty Coding Tips - Gamasutra article from the last issue of Game Developer magazine in June 2013, with nine real-world examples of dirty programming hacks and shortcuts to fix baffling bugs.
Street Fighter 2 - Polygon article giving an oral history from some of the original Capcom developers.
Super Mario Bros. 3 - A Japanese children's book on how video games are made, with a focus on this 1988 Famicom/NES classic and including many pictures of old development hardware and Nintendo employees.