When it comes to preventing the spread of germs, maybe the president is on to something with his fondness for fist bumps. The familiar knocking of knuckles spreads only one-twentieth the amount of bacteria that a handshake does, researchers report. That's better than a high-five, which still passes along less than half the amount as a handshake. So fist bumps -- popularized by Barack Obama and others - seem to be the wisest greeting, especially during cold and flu season, said researcher David Whitworth of Aberystwyth University in Wales/Associated Press. More here.

Question: I gave someone a fist bump less than 10 minutes ago, for giving me a good tip re: snow removal. When did you last give someone a fist bump? Why did you do it?