Sitting looking out the window it is not exactly summery outside. If you are looking for something to occuppy yourself for a while you could do worse than try out a revision crossword. They can be a good way to test your knowlege of a subject and to highlight items you may need to revise.
I have put a general maths revision crossword up here that you might like to try. You can do it on line, or print it off as either a word or PDF document. If you like, you can experiment with generating your own crosswords. Teachers might find it a useful resource for their classes.