Geogebra is a comprehensive FREE dynamic geometry program that can also be used to teach coordinate geometry and calculus.

http://www.geogebra.org/cms/

This Word document is a beginner's guide to Geogebra. Geogebra is a free dynamic geometry program available in both Windows and Mac format from
http://www.geogebra.org/cms/

This document gives a brief introduction to Geogebra in the context of circle geometry.
Thanks to David Crewe for sharing.

One key ingredient - maybe THE key ingredient - for students to be able to solve maths word problems is being able to VISUALISE what they read. The attached document gives you a step by step approach to teaching students how to visualise word problems as a key step to solving the problem. Thanks to Jude Ocean from RMIT in Melbourne Victoria for providing the core material for this document.

A maths version of hangman. There are links to a range of maths dictionaries if the class doesn't know the meaning of the word.

http://www.mathcats.com/explore/puzzles/mathmysterywords.html

Sniff out the clues and find the sneaky thief. A little bit of deductive reasoning, and an whole lot of fun!

http://pbskids.org/fetch/games/csi_1/game.html

Which one and only one of the nine arrows' tips points exactly into the centre of the respective circle?

http://www.puzzles.com/PuzzlePlayground/PointTheCenter/PointTheCenter.ht...

There are three coins placed as shown in the illustration. Can you slide the middle coin to the right until distance AB equals distance CD?

http://www.puzzles.com/PuzzlePlayground/CoinDistances/CoinDistances.htm

Doo-dahs are a wonderful way to bring information into a classroom discussion in a controlled manner. A Doo-Dah can contain text, annotations or images, even those added or created on the fly. A picture is worth a thousand words, so download the file and have a play. You will soon learn the power of doodahs!

If you have group competitions in your class, this is a neat way to keep a running score (up to a maximum of 30 points per team).

A wonderful collection of clocks. The time comes from your computer's system clock, so if that is correct, these clocks are as well.