From the people that brought you the Arctican comes the Chillsner, an insertable frozen metal straw (sort of) that keeps your favorite bottle of brew (or root beer, not judging) cool. Pretty genius if you ask me. Not sure how long the "in-bottle, drink through beer chiller" will keep it's freeze but still pretty dope. 

The Chillsner - 2 Pack for $30

If you still don't really get how it works, check out their video to get a little more of a walk through..