A short-lived ad campaign by Urban Dictionary that failed because too few of people wanted mugs with the likes of cleveland steamer, jalobes or scene to identify them before they've had their coffee.
Everyone knew that Jim meant business when he emerged from his cubical before 10am sporting his Urban Dictionarymoose knuckles coffee mug which he purchased through the get this def on a mug ad campaign.
Now your friends will look at your mug and know you do pointless crap like go on urban dictionary, look this very definition up and buy a mug with it printed on.