Find the Murderer - send one person out of the room. Quietly between the remaining guests choose a murderer.
Bring the 'detective' back into the room - everyone carries on as normal drinking, chatting, eating etc. The Murderer then begins winking at people who must die convincingly!! Scream. Arghh!! work well here!! or quietly if preferred!! The detective must guess who the Murderer is - hopefully before everyone is murdered and then you can play again with a new detective and murderer!! Silly game but fun!