Monday: Join the free talk and public debate, Rio 20+ Earth Summit: What should we do now? at St. Martin in the Fields from 7pm and see a new photography exhibition focusing on solutions to environmental problems while you're there (free).
Get a Dickens fix with a talk on Charles Dickens and the East End of London plus guest Martha Leigh, talking about her book, 'Memories of Wapping 1900 to 1960' in St George in the East from 6pm (tickets £5/4).
Photographers can go to the Julian Hawkins talk & demo "Facing it", thanks to City of London & Cripplegate Photographic Society, and learn how to create visually striking portrait photos away from a studio environment using flash, upstairs at The Horseshoe, 24, Clerkenwell Close, EC1R 0AG, 6.45pm - all welcome (free).
Take a walk On London's Oil Road: A journey to the heart of the energy economy with the Festival of Transition from 6.30pm-8.30pm (tickets £5).
Thursday: Homero Aridjis reads his poetry and is in conversation with novelist Ali Smith in Swedenborg Hall from 7pm (free but book your place).
Dinner is Served late at the V&A from 6.30-10pm exploring tableware and ceramics (free).
Saturday: Back in Hither Green, watch 1980s animated film Animalympics in Hither Green Hall at 1pm (50p).
The Building Exploratory host a market stall for Panorama High Street 2012 at the Idea Store Whitechapel to celebrate the architectural heritage of the historic high street with photo challenges, tours and interactive activities from 10am-4pm (free entry).
Party Spanish style in the courtyard outside Camino, Kings Cross with Fiesta en le Calle from 7pm-1am (free).
Sunday: The Chelsea Fringe is underway and there are loads of gardens, projects and pop-ups to visit. Try the restored Fulham Palace Walled Garden (free entry), Cake Sunday in Finsbury Park allotments (free) or the Kitchen Garden at Cremorne Gardens W10 (free).
It's also Big Nature Day with free family activities in the Wildlife Garden and Darwin Centre at the Natural History Museum (free).
Check out our things to do in London for free page for more.
Photo by sarahluv via the Londonist Flickrpool