My favorite classroom tool is Doceri. It does cost $30, but I use this iPad app every day, so it was well worth the cost. You need a computer (laptop/desktop), wireless network, and projector to use Doceri. It basically turns your computer into a whiteboard. You can control your computer and any files remotely from the iPad. I use this feature for PowerPoints during class. You can eccentrically take a screen shot of whatever is on your screen (or use a number of included backgrounds such as graph paper) and then write on that image. I use this feature most often. I will make a PowerPoint presentation of my notes each day and then use Doceri to annotate each slide. You have a ton of pen style/color choices so you can color code and highlight important parts of your class notes. Doceri can save each annotated image and you can email it to yourself in PDF form. This can become a document to post on your class website for absent students.
You can also use Doceri to display pictures that you take with the iPad’s camera. I will often take a picture of student work and display it to discuss as a class. Additionally, you can use Doceri to make your own videos if you are implementing a blended or flipped classroom.
I recently used Doceri to implement the Mathalicous lesson Blindsided.
Here is a screenshot from our discussion on how to adjust your rear view mirror:
Here is a screenshot of the most commonly used position of rear and side view mirrors:
Here is a screenshot of our discussion of the optimal mirror positions: