VLC has a nice feature which allows to play videos faster/slower without affecting the audio pitch. Can this be somehow achieved for YouTube videos as well?
You can change the speed of the video if you are in the HTML5 beta program. I am not sure about the audio pitch.
For example, here is a non-scientific (opinionated) breakdown of the video
At 2x speed: There sounds like there is a bit of pitch change but I cannot tell for sure based on the accents.
At 1.5x speed: No audible change of pitch (at least to me)
At 1/2x speed: The voices don't seem to drop to the lower pitch you would expect
At 1/4x speed: The audio drops completely
VLC Media Player (v1.1 on-wards) can play YouTube videos without affecting the sound pitch and without having to download the video separately.
Here are the steps:
UPDATE: You can have more control over YouTube's default HTML5 speed settings (without the audio pitch issue). Speed up YouTube Playback?
If you're using Windows 8, check out Media Player Plus (available in the App Store). It allows you to open YouTube videos (or your own local music/video files), then slow them down or speed them up without altering pitch.