The team at Desmos has two really good activities:

1.  Function Carnival–Students graph the motion on three rides.  They can do this in class on computers or iPads. The teacher dashboard rocks too.  I made a quick handout here.

2.  Des-man–students make faces using functions.  This will also help reinforce domain and range.  I have made a quick handout for that one too.

Updated 3/20:  Here is a quick video of the teacher dashboard for both the Function carnival (0:00-2:10) and Des-Man (2:10-End) that we did in our workshop with about 20 participants on using tablets in the classroom.  There is a little down time that I failed to edit out. I also want to give a big shout-out to Desmos for responding rapidly to a small issue we were having.