And so one of the most treasured weekends in London's calendar draws near. Open House, taking place this Saturday and Sunday, gives Londoners access to some 700 buildings, many of which are normally off-limits. We're only going to make one recommendation - go see St Anne's, Soho at all costs. The complex and hazardous climb to the top of the Soyuz-like spire is one of the most memorable and scary London adventures we've ever had. But what's your top tip? We're particularly interested in hearing about obscure but enchanting buildings in the outer boroughs, or really unexpected pleasures in the very centre of London. Fire away in the comments.