This fall, Poll Everywhere released an add-on to Google Slides that will insert live polls into Google Slides. While I love PearDeck, many of my teachers like to create their presentations in Google Slides - not in PearDeck. If you do it that way, you are VERY limited on the number you can create. So, this is a great solution for having quizzes embedded into presentations.
How does it work? Check out this post from Poll Everywhere. Then, check out Stylin' with Slides for more ways you can use Google Slides that you may not be currently using.
On fennovation.org, you can read about my favorite uses of the rest of the Google Apps. Check back each month for updates...and soon for a big update on Google Forms (I'm holding out until all of the features in the "old" Forms are available in the new Forms).