I bought a new geigercounter, a Gamma-Scout. I have nothing to test it with, but I think it react on the background-radiation. But I will try it on someone who has a smoke-detector. My own is optical, so there is not any radioactive material.
But I bought it because me and a friend will travel later this year I hope, to Chernobyl and Pripyat! It will be extremely exciting! I promise to take and publish cool pictures from it.
It was pretty expensive, but there came with a certificate, that it is calibrated with Cs-137.