Turd in the punchbowlIs another of my personal favorites, slightly akin to green weenie but even more repulsive. It's an ugly problem that pops up suddenly and must be taken care of as swiftly as possible. Although unexpected, it usually isn't hidden like a green weenie. Also, it can refer to something done intentionally in order to foul you up. (See also: Binaca blast for the opposite.)
Turd in the punchbowl
an illustration by Gahan Wilson from Ron's Book "Green Weenies and Due Diligence"
Ron Sturgeon's Books :: Mr Mission Possible
Green Weenies and Due Diligence
Getting To YES With Your Banker21 Secrets to get your small business funded
Taking pre-orders. Available Fall 2010
Peer Benchmarking GroupsOne Entrepreneur's Story of Extreme Success
Taking pre-orders. Available Spring 2011