This not only allows students to use any web-enabled device to respond to quizzes or polls, but students can use it to submit and vote on questions. One of my favorite features is the "confusion barometer."
The link in the textbook is out of date, so thought I'd share the correct one. I've been using this template for a couple years and my students LOVE it. I give each group a small whiteboard and a marker to put their answers on and the built-in scoreboard makes running the game easy.
This is one of my favorite YouTube channels for the classroom. For each episode, he selects an interesting physics question, then does a roughly 1 minute long video answering in a clear, engaging way with the help of hand-drawn diagrams.
This website has a great collection of science demos on a wide variety of subjects. For most, they have a video showing the demonstration along with a blog post that provides the explanation and tips for a teacher performing it.
This is a phenomenal collection of science simulations. I've used them both as a demonstration on my SMARTboard to drive home some point and as labs where students use the simulations to discover key points on their own.