13. Pick Up A Stylish Umbrella

These purveyors of finest umbrellas have been around since 1830 and have sold brollies to leading British luminaries over the years, including a UK prime minister or two. The shop itself is a sight to behold, worthy of the props department on Mary Poppins, with many of the original Victorian fittings and an amazing selection of walking sticks and animal head umbrellas on display, as well as the more modern, lightweight kind that will fit in your handbag. It's certainly worth a browse, even if you do end up buying a cheap-o one from a street vendor in Leicester Square.
12. Visit The Singing Ticket Barrier

There's an unsubstantiated rumour that the barrier will be duetting with Katy Perry on the next series of the X-Factor, but before it picks up a record deal, head down to Canary Wharf to hear it sing, all for the price of a single tube fare.
Check out the barrier in action:
http://www.youtube.com/watch?v=3cc12dU1u0Y