Many of us have whiled away an afternoon arguing with strangers on the internet about football's biggest question - Messi or Ronaldo?
Usually all you get at the end of the debate is the sense that you've wasted your afternoon, but charity the Hubbub Project has found a way to put the competition between the world's biggest stars to good use.
Hubbub, which aims to "bring people together as a force for good", is allowing Londoners to vote for their favourite player, while simultaneously cleaning up the capital's streets.
Pedestrians can show their support for Lionel Messi or Cristiano Ronaldo by putting out cigarettes in slots marked with the name of one of the two players.
You don't even have to be a smoker to take part - just pick a cigarette butt off the street and cast your vote.
The Portuguese international seems to have opened up an early lead, but there's still time for Messi to drag it back.
https://twitter.com/insidewldftball/status/639376993180614656
