Using the AppleTV instead of a projector (or worse, interactive whiteboard):
Using my iPad and AirPlay, I can wirelessly mirror any content on my iPad to the screen at the front of the room. The real advantage is evident during collaborative activities. Students can use their own iOS devices to connect to the AppleTV to share their work with the rest of the class. I can be anywhere in the room and still run my lesson. I can pull up sound and video clips on my iPad and instantly share them with my class without being attached to any particular location in the room.
There’s so much potential here, especially with AirPlay support for Macs in Mountain Lion. TVs are cheaper and higher-resolution than most projectors, too.