Favorite factoid: one (discontinued) power source for pacemakers is evidently Pu-238.<p><a href="http:&#x2F;&#x2F;osrp.lanl.gov&#x2F;pacemakers.shtml" rel="nofollow">http:&#x2F;&#x2F;osrp.lanl.gov&#x2F;pacemakers.shtml</a>