(See above for a how-to screencast.)
You can watch many audio-heavy videos online at 2x speed and not lose any comprehension. For a two hour video, that saves you an hour of listening time.
You can speed up YouTube videos easily using the speed controls built into the player. Vimeo videos have no such built-in controls so we have to get creative. The trick is to create a bookmarklet in your Chrome or Safari browsers (this doesn’t work in Firefox, sorry).
Give the bookmarklet whatever name you like, and paste in the following code as the address/URL:
Then go load up a Vimeo video page, click the bookmarklet, enter the playback speed (e.g. 2 or 1.5), and click okay. Now when you play the video, it will run at the speed you specified.
Test it out here:
UPDATE: Check out Scott’s comment below for even better ways to manipulate Vimeo playback.