The host was absent, but more than 400 people turned up at the artist's million-dollar studio 600 miles away in suburban Shanghai to bid farewell to the structure that he was told by officials had been marked for demolition, purportedly for violating local land-use rules.
Undeterred that Ai was under house arrest in Beijing and unable to travel to his own party, the guests turned the event into a light-hearted parody of China's often ham-fisted application of bureaucratic order.
Eating river crab - he xie - which in Chinese is a phonetic play on the government's campaign for social harmony, the guests laughed at the irony.
In a harmonious society, we eat river crabs," the guests chanted, as some posed for photos in front of banners and crowded into the two-storey structure's courtyard and expansive rooms.
The Tate Modern in London is currently hosting a solo exhibition of Ai's work at its Turbine Hall.