Hundreds of schools across the world took part in a day of events earlier this month in which pupils stacked plastic cups into formations, then swiftly disassembled the piles against the clock.
The phrase "cup-stacking" is frowned upon by organisers of the event, who prefer to call it "sport stacking" to emphasise that - no, no, really - it is a sport.
The World Sport Stacking Association reports that it got 125,579 people from 684 schools and other organisations stacking for at least 30 minutes on the same day.
Among them were 54 pupils from Southend High School for Girls in Essex, which has only had a sport stacking team since October.
The club is organised by Sarah Imbush, head of maths, who said the game improved pupils' hand-eye co-ordination and creativity.
She told the Castle Point Evening Echo: "I hope to get more schools involved by doing stacking relays ... It makes it more physical too."
Physical - not the first word most people relate to cup-stacking.