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.