Google’s Wonder Wheel
Browsing around the LinkedIn Q&A I came accross somebody mentioning Google’s Wonder Wheel new-ish feature, and had to give it a try. It works similarly to mindmaps, and allows you to refine your search by clicking on related searches in a cute graphic way.

Google's WonderWheel example
So, searched for “London”, clicked on “More options” and then the Wonder Wheel option (Under Standard View, next to the Timeline view, down the left hand menu).
So, London offers lots of related searches, such as “facts about London”, or “London Pictures”. Clicking on “London Pictures” expands the graph with more options related to that second search.
For people like me who love just randomly searching around, it looks like an awesome tool. You can also use it when you’re not really sure of what are you looking for, such as when trying to find a film title when you only remember a few things about the film itself.
If you want to read more about it, checkout the Google Wonder Wheel official site.