Timeblog.net

Just sit back and think for a moment, what would be the worst place to install a gigantic Physics experiment? Several kilometres under the South Pole? Maybe, but exactly this is done with the Ice Cube Neutrino Observatory!
Neutrinos are lazy bastards, they don’t interact much. Each second, countless neutrinos pass through your body (and through the earth) without any reaction. But, this is a good thing from the viewpoint of cosmologists: No other particle from far away galaxies has the chance to travel to earth and be observed here without decaying or being influenced by fields beforehand. If we observe the neutrinos reaching earth and calculate their energy and their density and which direction they came from, we can retrieve information about many things: Far away galaxies, dark matter, ultimately about the origin of the universe.
So, if you want to detect neutrinos, you measure what happens if one of these small particles does react with your medium. As they are so lazy to react, you need a big medium: How about a cubic kilometre of ice? We have that at the south pole. You only need to inject some detector, in this case light-sensitive tubes that use a way of detecting the products of a neutrino reaction by measuring the emitte dlight, so called Cherenkov light. The Cherenkov effect works as follows: A particle travelling at near light speed in one medium enters into a new medium, where the speed of light is lower (e.g. the speed of light is 25% in water than in vacuum). If the travelling speed happens to be faster than the speed of light in that medium, the particle will emit light, the Cherenkov light we can detect the particle with. In the case of Ice Cube or it predecessor AMANDA, the neutrino that crashes into an ice atom will produce a muon that can be detected by its Cherenkov light signature. As the ratio of non-neutriono-produced muons to other muons is about 1:1000000, the observatory doesn’t look into the sky from the south pole, it rather looks through the earth to the earth, and uses the earth as a filter for other muons!
With special hot water drills, 2.5 km deep holes are getting drilled to insert 80 strings with 60 optical sensors each of the course of 6 years, connected to a surface data collecting unit. Ice Cube will collect data for 20 years.

Sources:
IceCube Homepage with IceCube Gallery
University of Wisconsin-Madison
Wikipedia on Cherenkov radiation
LBLN/Press and Public Interest