Flashmobbing, the favoured pastime of bored students and the radically hip, lost some of its radical edge today with one of the first ever publicity stunt flashmobs.

The UK's largest volunteering agency, Community Service Volunteers (CSV), took on internet culture's latest trend for spontaneous and pointless gatherings organised by email and text message by inviting 500 people to flashmob Charing Cross Library in central London to celebrate the release of its report, Lending Time.

"The idea came from one of our directors, who read an article about flashmobs in the New Statesman. He thought: 'Why don't we give it a whirl and put the point back into flashmobs and give them a different spin?'" said a CSV spokesman, Jason Tanner. "They're usually so pointless."

The charity alerted members of its London volunteers database by email and asked mobbers to bring in unwanted books for donation to schools in exchange for a mince pie, a bookmark or a copy of Lending Time, which outlines CSV's volunteering strategy over the next three years.

Mr Tanner said: "We wanted to make the point that volunteering can be for a minute or for an hour. It's anything that makes a difference to someone's life."

The event had been a great success, he said, with about 100 people turning up to donate more than 500 books.

"The volunteers were really excited," he said. "At first they were very hesitant and wondered: 'How do I flashmob?' But we gave them a mince pie and they soon relaxed.

"The people already in the library went about their business and didn't seem at all phased, although there were a few raised eyebrows and a few wanted a mince pie, too."