Music Buzz Play tunes by clicking different points in the video slider. This is a completely absurd way to try and play music. (I've linked some more fun YouTube hacks below.) Via Make.
http://www.mattcutts.com/blog/link-to-youtube-minute-second/
This is just unbelievably useful. Sometimes you want to show someone a specific part of a long video, or illustrate a point with a scene that's relevant three minutes in, but not at the beginning. Best YouTube hack ever - it never even occurred to me that I could do this. Note: You can also link to the high quality version of a video by following these instructions.