I want to make a custom heat-sink sleeve contraption for my MBP. It would be a station that the body of my laptops sits in....rather suspended in.... and in the station would be extremely cold temperatures. Kind of like a freezer. There would be a roof and a floor and sides on 3 sides and an opening where I can slide the laptop in. Then, have a border so no condensation touches the computer to avoid water damage. Then, have liquid nitrogen or something frozen, looping around the laptop, then heated by the air around the computer, then cooled once risen by fans, like a heat sink.

Here are my questions:
How cold can a CPU get before damage/shut down (i5 2.4GHz MBP 520m I believe)?
What should I make it out of?
And what cooling agent should I use?

They've been using liquid nitrogen for cooling for over 10 years. Here's some people who got their CPU down to -190C in 2003 - http://www.tomshardware.com/reviews/5-ghz-project,731.html

Lots more at http://www.google.com/search?q=computer+liquid+nitrogen+cooling

You really have no idea what you're doing. Condensation occurs when the computer comes OUT of the cold and comes in contact with warm air. Existing systems that use liquid nitrogen take some very specific precautions against condensation, such as dielectric gel, something you won't want to slather all over your Macbook Pro.

Assuming you could even remotely build this contraption, you're well on your way to destroying that Macbook Pro.

This is hilarious!