For instance, coming up later this month will be the Notting Hill Carnival, the biggest street party in Europe, and in many ways as good as anything elsewhere in the world. Many people will have been preparing for this spectacular event for months already, and I'm sure they will be becoming increasingly excited as the weekend draws near.
Of course there is all the theatre and arts to keep you busy .. if you have a particular love of culture. In London you are certainly spoiled for choice.
And it can be interesting and pleasant enough just to wander around. If you don't already know London well, then I definitely suggest the walk between London Eye and Tower Bridge, and a few hundred metres beyond. There is an amazing amount to look at along the way, on both sides of the Thames river, and you can easily enough take a break at the very popular Tate Modern gallery.
You can be a bit more adventurous in your walking, and explore different parts of London. For instance, what about going to a part which you have never seen previously, and try to find as much of interest as you can. Alternatively, buy one of the many books of walks around London, and follow the prescribed routes, reading about the places of particular distinctiveness along the way.
Or, if you are not feeling particularly energetic, go to a nearby park and enjoy the relaxing experience of absorbing your feelings of the natural surrounds. If you have children, they will definitely enjoy running around, making the most of their greater freedom.
This summary has only touched on some of the things you can see and do in London. In later postings I go into more detail on different aspects to encourage you to make the most of London.
Here's a video of Notting Hill Carnival: see if you can feel the excitement.