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.
If you want a peaceful day out of the busy city, Highgate doesn't really feel like London. The cemetery is interesting and peaceful, there's a tour of the old half which is definitely worth the money. Karl Marx, among others are buried there.
The Thames is not traditionally the prettiest river but it has its moments. Here it is turning pink in a sunset this summer. Its the reason the city is here and I like how in moments of real importance it rises to the occasion. For the golden Jubilee the queen floated down it with hundreds of boats, it was an amazing sight, like vikings setting out for battle. Good river spots - North Bank Savoy Gardens, Royal Festival Hall.
There are three branches of this South Indian Vegetarian Restaurants across London, two in the West End. They all look pretty unremarkable from the outside, the décor is pretty basic, but don't be fooled - the food is wonderful! It's incredibly cheap and the friendly staff cater for vegans and people with food intolerances really well.