Archbishops Park, every Saturday morning 10-12. Two hours free football coaching organised by the Sports Action Zone. It does not seem to be promoted so numbers have dwindled from 60 odd a few years ago to about 5 or 6 now. My son, also 11, would be delighted to see some new faces. (Though kids from aged 6 up are welcome.)
Great if others could spread the word to friends and neighbours as sports are hard to find in the area and we should make the most of what we have.
Southwark have an Autumn multisport community games scheme from 25.9.07 - mid Dec., for 8-16yr olds. On Tue & Fri in Elim Estate Playground, Wed in Geraldine Mary Harmsworth Park & Thu in Mint St Adventure playground, all 5-6pm. The website is still showing the summer scheme, but there are contact no's to call for more info. www.southwark.gov.uk/communitygames
Also worth knowing about is the SCC cricket scheme at the Oval. It can be a bit hard to find details, and you would probably need to book now for January, but it takes place in the indoor training centre and so is a wonderful opportunity.
For swimmers, the Queen Mother Sports Centre hosts the Westminister Swimming Club which trains regularly and swims in leagues.
Rugby, I think you need to go south. Friends kids go to Battersea Ironsides which trains in Tooting. But I think there are also clubs operating out of Dulwich College and Alleyns which are not limited to pupils. Also I think there was a club in Brixton. Southwark Sports Dept should know about the middle two and Lambeth the fourth.