ID a Classical Piece

[Helium_Junkie]

http://video.stumbleupon.com/#p=67trh7po7s

I know the tune, but not the name, if anyone can help I'd be very grateful

 

[Alan!]

....

 

[gillywibble]

In the hall of the mountain king.

Edit: bah, beaten.

 

[Helium_Junkie]

Excellent! Thank you both