Happy Mandela Day: 67 minutes of charitable acts for 67 years of public service

Teachers and students from The Lukho Lwen School hold cards wishing former South African Nelson Mandela a happy birthday on Mandela Day in Soweto (Getty Images)

While former South African president Nelson Mandela spends his 95th birthday in hospital in Pretoria, the rest of the world has been urged to take part in International Nelson Mandela Day by spending 67 minutes on charitable acts.

The number marks Mandela's 67 years of public service, and the day is a call to individuals everywhere to try to make the world a better place one small step at a time, as volunteers paint schools, biker gangs clean streets and politicians devote time to worthy projects.

On Twitter, South Africans and people all over the world shared how they are participating in Mandela Day: