Construction lite

Today in two different classes we used apps to help the students learn.
In the college prep math class we used free graphing calculator to learn what the graphs of sin and cos looked like and what happens if you add this or that to the equation.  We discussed it, played with equations and the kids really had a blast.
We started with y = sinx.  I took time to have them read the unit circle so that we could connect the unit circle to the sin graph.   They graphed y = 3sinx on a different line so they could have both equations on the screen at once.  This way they were able to tell me what happened to the graph by adding the 3.  I had them graph y = sinx + 2,  y = sin(x+pi/2) and y = 3sin(x + pi/2)+2.  After comparing and contrasting the graphs, I was able to lead them to seeing how the transformations from earlier math classes applied to trig graphs.  It was awesome.
I downloaded and had my geometry students use construction lite which simulates using the compass and straightedge.  The first two sections are unlocked in this free version of the app.  The sections are lines and angles.  We looked at copying a segment and constructing a perpendicular bisector.  The app shows the student how to do each activity and then allows them to do it themselves using the digital compass and straightedge. 
I just let my students loose to try the sections themselves and as one figured out how to do something, I would have him or her go help others so those who finished early were working as peer tutors with the others.  Although only two topics are available, there is a sketch function that will allow me to have students follow the construction directions in the books and I don't have to keep track of all the compasses, pencils etc.  The kids enjoyed themselves.