A comedy club in Barcelona is experimenting with charging users per laugh, using facial-recognition technology to track how much they enjoyed the show.
The software is installed on tablets attached to the back of each seat at the Teatreneu club.
Each laugh is charged at 0.30 euros (23p) with a cap of 24 euros (£18). Takings are up so far.
The project was developed to combat falling audience numbers.
Partnering with advertising agency The Cyranos McCann, the experiment was a reaction to increased government taxes on theatre tickets, which in turn led to drastic drops in audience numbers.
The results of the experiment have so far proved positive with overall ticket prices up by 6 euros, according to the theatre.
The system is now being copied in other theatres around Spain.
The comedy club has also launched a mobile app as a method of payment, as well as its first pay-per-laugh season ticket.
James Woroniecki, director of London's 99 Club, said: "Sounds fun, just so long as all the facial recognition data doesn't get forwarded to the NSA [US National Security Agency].
"It'd be a big technical challenge - as people laugh so often at the 99 we'd have to install a cash machine by every seat."