iToys

Or rather: hardware accessories for iPads and iPhones. Apple obviously makes it very difficult to connect much of anything to their iOS devices (in stark contrast to Android-based gizmos). That being said - there are some interesting things that you can attach and even use for teaching and learning"

1. External Bluetooth keyboards are pretty popular in coffee shops these days, for example this one.
2. iCelsius makes a whole range of temperature and humidity probes - this one would work great for the Thanksgiving Turkey.
3. Node is a sensor platform for connecting more sensors (climate, air quality, surface temperature, etc.) to your iOS device via Bluetooth.
4. The FLIR ONE turns your iPhone 5/5s into a thermal imaging camera.
5. Too expensive? The free Hukseflux Pyranometer app and diffusor allows you to measure solar irradiance with your iPhone.
6. This is not a real accessory, but for $10 at the hardware store and a cheap laser pointer you can turn your smartphone into a digital microscope!