To get this topic rolling, here's my best two:
(i) Snail bait. The slugs and snails don't seem to care too much what they drink. And they get the Saddam Hussein of hangovers.
(ii) Social grenades. When it's time to clear the room of guests, pull out the duds and lob them into the crowd. Look as though you're enjoying it when everyone else is clearly not, pump it up as a session beer, settle back and watch the bail-out excuses roll in.