Theory stuff - a taster of what Computer science is really like
This guy is very good, I like both of these although I don't agree with everything he says :). These two lectures will give you a good overview of one of the main theory components of Computer Science.
Your programming project
Re-create all or part of your GCSE project using C#. There's a catch though, you are not allowed to use Access to provide the data back-end, you must create the files yourself using the file facilities in C#.
You'll need to learn how to create efficient files and read and write data.
For extra credit, create and use your own Objects to manipulate the data when it is read. This will require an experimentation with Object Oriented Programming. This is a notoriously tricky area and you shouldn't worry too much if you find it very difficult. It is.
Starting from scratch and using the most advanced features that you can find, create an interactive program which will allow the user to draw pictures with the mouse.
As well as basic free-form lines, can you add arrow shaped graphic objects which can be placed and then subsequently edited by the user, clicking and dragging using the mouse. The aim is to have a program which could work on an interactive whiteboard. It will allow the user of the board (which is basically a big screen with mouse clicks) to draw arrows all over the screen and subsequently rearrange them by clicking on hot-spots.
Once again you'll get extra credit for using Object oriented techniques.