The topic is rather self-explanatory. Post the YouTube videos you've come across that struck at your scientific soul with their wit, wisdom, or beauty.

 

I'll start off with this scene from Carl Sagan's Cosmos, a pictorial representation of evolution:

http://www.youtube.com/watch?v=EYzx6C4irsI

that mooeypoo is an alcoholic.

 

And there's the introduction to

that Azrienoch did.

Ah, the old classic Powers of Ten, which I'm sure most people will have seen...

 

http://www.youtube.com/watch?v=BBsOeLcUARw

Ohhh. That reminds me... IMAX - Cosmic Voyage:

 

http://video.google.com/videoplay?docid=5757507304603419799&q=imax&total=3063&start=0&num=10&so=0&type=search&plindex=1

And you have

I for one welcome our ape overlords.

The ones at this link are, quite simply, stunning. Once you've viewed the animation on the homepage, be sure to go to the bottom right and click "Media" for more:

 

http://multimedia.mcb.harvard.edu/

 

 

 

Also, swansont's recent blog post:

http://listverse.com/science/top-10-amazing-chemical-reactions/

 

Pure awesome.

How to turn a sphere inside out:

 

http://video.google.com/videoplay?docid=-6626464599825291409