Never been physically thrown out, but I was asked to leave once because I got in argument with a group of kids who harassed one of my friend's girlfriends and were grabbing her and shit!
Another time, LOL this was funny... I was 20 years old, tried to get into a club, bouncer tells me I have to be 21 and doesn't let me in... eventually I sneak in, and 20 mins later he finds me and asks me to leave... whats funny is that I was 230 lbs at that time, and he was maybe 160 and SHORT... dude was staring up at me and looked very nervous as he was telling me! I just smiled and said "Alright, I don't want to get you in trouble" and walked out!