The boss did a favor for an old friend and had me take them on a flight seeing tour. On the way we circled their house for photos and while doing so my window popped open (not unheard of to unlatch the window by accident with your arm). I pulled it closed and noticed the guy behind me had his fingers in the window when I closed it. After just a moment it popped open again si I turned to see WTF was going on and see this guy try to puke out the side window. 140 mph wind blast blew it right back into his face, covered his girlfriend seated behind him and flew around the cockpit onto the instrument panel. (It appeared he had a chocolate malt mixed with beer). I was not happy. Landed at the nearest airport so handsomehunk and his family could clean the plane (they had a choice, clean or walk) and chewed dunderheads bellybutton for opening the window and for not telling me he was ill. Come to find out this guy gets sick every time he flies. Left him there, continued the flight with remaining pax.