A piece of firewood....maybe 3 or 4 inches in diameter...at 70 mph on my morning commute to work. 3 lane highway....lots of congestion...I couldn't see too far in front of me because of the bumper to bumper traffic....all of the sudden...BANG...rode right over the top of it on my GSX-R750. Other than scaring the shit out of me, no harm was done. Tires and rims both survived the impact with no worries. My underwear were definitely a casualty, though.