I previously wrote about a game that I had students build as part of our Meteor app building unit.
Here's another video series that would be of much better use to teachers: Have students vote on an answer to a question. The example I gave in class was of students voting on which picture of my dog Mileaux was the best.
This is a fairly simple application of Meteor principles that could be useful in a classroom setting. Since it's all done on MeteorPad, you don't have to install anything on your computer. If you threw this together, and then wanted to actually give it to a class, you could give them the link highlighted in red in the image below. NOTE: This link will change whenever you reload the Meteorpad page, so make sure you share the one corresponding to your instance of the application.
You can visit the fully functioning code and try it out at this link:
VoteForMileaux - MeteorPad