Did you know that sleeping next to someone blitzes you with 0.05 millionth of a sievert of radiation per night? That eating a banana gives you 0.1 millionth, and that a day’s dose at the Fukushima Daiichi nuclear plant would give you .0036 sieverts?
For some great perspective on the doses of radiation and what we’re exposed to in both everyday and extraordinary circumstances is a superb radiation dose chart from XKCD.