http://imgs.xkcd.com/blag/radiation.png (or click the link if it doesn't work).
Makes you think about the 18mSv you get from an hour in Terras (3x immediately outside chernobyl) or the 12000Bq in old gunnislake.
Puts in nicely in context, I think
I forget the "I live in camborne" level. 153mSv/A?
Edited to remove huge mutant image.