Since yesterday, all YouTube videos have a red / pink tint. Vimeo and other video sites are working.
It seems strange that it's only on YouTube, but since other people I asked don't have this problem, I think it's a Flash plugin problem.
It does this on all my browsers.
Saw this this morning, http://www.webupd8.org/2011/03/fix-pinkred-youtube-videos-bug-using.html
Which by the way this is a fantastic site to have in your feed reader.
Disable hardware acceleration in flash. Normally, this is done by finding a flash object, right clicking it and unchecking hardware acceleration.