A fantastic implementation of the 'bath graph', ie the graph of water height vs time if a bath tap is turned on/off, and/or the plug is pulled out, and/or a person gets into/out of the bath. And a yellow duckie is included for free. Three thumbs up!

http://www.mathsonline.co.uk/nonmembers/gamesroom/sims/archi/archi4.html

A Java applet in which students can change the number of points and the correlation coefficients, as well as add points. They can also show the regression line and the residual plot. Three thumbs up!
http://stat-www.berkeley.edu/~stark/Java/Html/Correlation.htm

Six points are shown along with a line that passes near them. The applet shows the square of the residual of each point as well as the sum of the squares. Your task is to change the gradient and y-intercept of the line to minimise the sum of the squares. Three thumbs up!

http://www.dynamicgeometry.com/JavaSketchpad/Gallery/Other_Explorations_...

Add some points to the scatterplot. The applet will calculate the correlation coefficient and the sum of squares. You can also choose to show the least-squares regression line and the x-mean and y-mean lines. Very instructive!

http://bcs.whfreeman.com/yates2e/pages/bcs-main.asp?v=category&s=00020&n...

Type in the Input. The Function Machine applies the function and produces the Output. If you choose [Random], you will have to use some brainpower to figure out the hidden function.
http://www.amblesideprimary.com/ambleweb/mentalmaths/functionmachines.ht...

Linear Function Machine
With this function machine, you have to enter the correct linear function, using algebra.
http://www.shodor.org/interactivate/activities/LinearFunctMachine/

A triangle is made up of four pieces. Move the pieces around to make a new congruent triangle. Except the new triangle is missing one square unit! Where did it go?

An interactive animation illustrating the sequence described by the nth term expression, 4n - 1, where n corresponds to the number of potatoes. Drag the potatoes into the microwave to see the time required to cook them. Click the arrow button to reset the animation.
http://www.yenka.com/freecontent/item.action?quick=mb#

Explore the graphs of functions interactively.
http://nlvm.usu.edu/en/nav/frames_asid_109_g_3_t_1.html?open=activities&...

Students use a TI-Nspire calculator to investigate coordinates of points and the gradients (slope) and equations of linear functions.
http://www.tialgebra.com/activities/algebra_i/335/

A TI-Nspire activity. In this activity, students investigate the total cost of a private party at each of three restaurants. Each restaurant states its pricing information differently, but all charge a flat room fee (represented by the y-intercept) plus a per guest plate fee (represented by the slope). Students model the cost of a party at each restaurant with the graph of a linear function.

Dinner Party Activity
http://education.ti.com/educationportal/activityexchange/download_file.j...