Autograph

Intuitive graph plotting program, that allows for 2D or 3D curves, vectors, sets of points, statistical data and much more. Very simple to learn, and with features such as slow plotting and animation of changes of variables with respect to time, Autograph can greatly aid students' engagement and comprehension.

KeepVid

If you've seen a good video to teach with on YouTube or another streaming video site, but your school network is blocking the website, KeepVid is a solution. Type the URL of the video you want into KeepVid, and it will produce a version of the video that you can download, and then play in your lesson from your hard drive.

The help page has instructions for downloading videos from OpenMaths using the KeepVid website.

NRICH

A collection of puzzles and activities, updated monthly, aimed at higher-attaining students. An active community provide solutions and additional, interesting ideas and concepts. More than 2,500 puzzles, on most topics on the syllabus, means a good chance of finding an appropriate extension or enrichment task.

Wolfram|Alpha

Described by its creators as a 'computational knowledge engine', Wolfram|Alpha is a search engine which, instead of giving websites as results, gives empirical data. Searching for any date will give its history and position in the calendar, for instance; any country will yield population, geographical and economic data; and any equation will, amongst many other things, plot an appropriate graph.

Although Wolfram|Alpha is still in beta, and so may not always return values you had hoped for, it is a project of impressive scope and is already quite useful at giving comprehensive information quickly.