Even if you can't make the date to see the Mayor, then City Hall is still worth a visit. (Craig's written a separate review of City Hall as well.) The public can go inside and climb the spiral ramp to the second floor, where you'll find the assembly chamber. The spiral ramp has some great views of the Thames, including a very fine one of the Tower of London across the water. The lower-ground floor usually contains a London-themed exhibition of photos, drawings or stories. There is a cafe downstairs as well, where you can have a bite to eat, and rub shoulders with the City Hall staff and eavesdrop on their conversations.