There are many quirky book stores in London, but I really love the selection that Daunt Books have, they often have bespoke editions which you won't find in other book stores. Also, the people that work there are so helpful and knowledgable. I can never stop myself from walking in!
Not the most exciting place inside, but a lovely rooftop area which not all that many people seem to know about, 2 mins walk from Old St station. If it's packed then The Red Lion is just up the road.
The Greenwich Observatory with its green laser beam can transfigure any night sky. If you decide to cross the Thames via the foot tunnel, make sure you look out for the green ray. You can be on one side of the meridian in a minute, and cross to the other side on the next, without even realising it.
There's something about this street, probably the fact that it's pedestrianised, that makes it feel like holidays. It also has a solid range of bars (Cafe Kick), restaurants (Berber & Q) and cafes (Brill) so is a good option for all times of the day. They have a quality variety of street food vendors operatin during the day, and fairy lights help it to come alive at night