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.