Wikitude is a free app that does a lot of cool things such as tell you where you can get food of your choice nearby, see if friends are near and more. But while I love using smartphone for positive gain in the classroom, one thing it can also do is see where Tweets are being made (and what is said on them). You just hold up the phone and you will see where the Tweets are coming from. You can also set the distance from a few feet up to one-half mile away. Since kids love using Twitter, it will be a good way to control it in class and use the phone positively. Thanks to my fellow online teacher, John Downes, for the tip.