If you need to display a working scientific calculator to the whole class, look no further.
You can also download a free virtual four-function calculator that can be carried with you, eg on a memory stick.
For ActivStudio software. 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.
Click on Edit and paste in a list of student names or words.
A virtual geoboard. A very nice implementation.
The Magic Magnifying Glass can be used to reveal hidden words and pictures.
For those who don't have either Equation Editor or MathType at hand, here is a free on-line equation editor. I had a play with it, and it seems to be very good: