If you are interested in learning more about astrophysics, the Institue of Astronomy hosts a range of different outreach activities. They are both entertaining and educational: everyone should get involved!
There is an public open evening every Wednesday during the winter season. You may expect a talk and, weather permitting, observing using the Institute's historic telescopes as well as some more modern telescopes courtesy of the Cambridge Astronomical Association. I have given a talks on solar neutrinos, the Earth's gravity, detecting gravitational waves in space and the Big Bang.
The Institute also opens its doors every year as part of the Cambridge Science Festival; the IoA open afternoon has activities for all the family. I made a gravitational wave wordsearch for the 2013 event.