During the year, there are loads of free events in London, e.g. St. Patricks Day, Chinese New Year, West End Live.
Walk in the Parks
There are so many parks in London, my favourite is Hyde Park.
London Open Houses
This is a free event in September, check the website for next years dates. There are over 750 buildings that are free to visit over a weekend, for example take a tour of The Bank of England and touch a gold bar!
West End Live
This is a free event usually hosted at Leicester Square, but this year (2011) it was hosted at Trafalgar Square. It's a show case for London's West End and features a taster from each of the Shows, live performances and Free. This year I stood in the lovely rain and heard The Phantom sing (Love Never Dies), and then watched the children from Billy Elliot dance (Billy Elliot). I then went into The National Gallery to visit my painting Georges-Pierre Seurat's Bathers at Asnières for a little while and when I came out, there was the cast of We Will Rock You murdering Queen's songs. Poor old Freddie Mercury must have been spinning in his grave R.I.P.