One afternoon when Danny Wallace was very bored he decided to place an advert in a paper which read simply 'join me'.
Danny Wallace gives an old lady a pot plant
He had no idea what he wanted people to join him for, but when the number of replies grew he thought he would use his new collective for good.
Whether it is giving a stranger a pot plant at Roman Road market in Bethnal Green, or handing a pensioner a scratchcard, his mission statement is to be nice.
The founder of Join Me and his 3,000 followers carry out 'random acts of kindness' every Friday.
"It's nothing that is going to change the world or anything like that but it is something that can light up someone's life, even if it is for just 10 seconds," Mr Wallace said.
"It's a really weird, sort of underground way to it - almost like a prank.
I'm thinking of taking the cult to America - the home of the cult
"You just kind of walk up to them, do something nice for them like hand them a pot plant, and then walk off. And that's it."
At his flat in east London Mr Wallace, 27, a writer and journalist, collects the letters and photographs of those who want to join.
Among those describing their good deeds was a man who got up early one Friday to wash all his neighbours' cars.
The group first met in December but usually keep in touch through email and the website.
Mr Wallace is now thinking of expanding.
"I'm thinking of taking the cult to America - the home of the cult," he said.
"I'm going to launch the American Karma Army."
Meanwhile he hopes to continue to bring smiles to jaded Londoners.