During an adventure in which they invaded the BBEG's keep, the party came across the BBEG's bedroom. I described the bedroom and rolled the obligatory search checks and the party looted the room of any valuables.
When I asked what they were doing next, the player playing the wizard stated that he was going to 'short sheet' the BBEG's bed and put smoke sticks into the ends of the BBEG's cigars in the humador on the desk.
Then there was the time in the Arcana Evolved campaign when the party just killed off some magister and to ensure he was dead, they cut the head off the body. They heard guards coming and the room they were in had only one exit. The party decided to hide and all found someplace to hide except the half giant warmain, who was too large.
I announced they could hear the door handle being turned and the half-giant was still in view. The half-giant took the severed head of the magister, put it upright on his shoulder and then tried to convince the guards that just burst into the room that he was an Ettin henchman of the BBEG....