Researchers have found that shining a laser on some special materials can cause that material to cool. The mechanism that causes the cooling is based on phonon interaction and the excitation of electrons. Basically a material will absorb light of particular frequencies if they correspond to energy level differences for electrons. By absorbing the light, the electron is excited to a higher energy level. If the frequency of light to too small, the electron won't have the energy to make the transition to the higher energy state. However, if some of the energy comes from phonons (vibrations in the lattice of the material) and the combination of the phonon energy and light energy is high enough, the electron can make that transition. Since by using the phonon you are reducing the total vibrational energy of the lattice, and vibrational energy is simply kinetic energy of molecules, which is what temperature is, you are reducing the temperature of the material.
Of course, the material has to be just a particular way in order to have the phonons and the light to interact in such a way that the resultant energy matches that which is required for an electron excitation. Still in this age of designed materials, it is possible. Imagine, no noisey fridges or AC's. Just silent laser cooling, that sounds good to me.
http://focus.aps.org/story/v18/st2
Laser cooling...
