Lot's of scenes in Step Brothers for me (and the bunk bed scene the hardest), but I have to say one of the funnier moments of seeing someone fall out of their chair laughing was watching Christmas Vacation at my buddy's house with his dad, who had never seen it before. So we start watching and his dad is on the verge of losing it by the time Eddie shows up, but when we got to the sled scene, he fell out of his chair laughing so hard we thought he was having a heart attack. It took him almost 30 seconds to recover and stop us from calling an ambulance.