You've got some downtime for some of your students since they finished their work early. Rather than giving them a book to read or another activity to complete, you give them permission to "play" on a computer or another mobile device in your classroom.
Last month, I had the opportunity to attend the SMART Exemplary Educator (SEE) Summit 2015 in Calgary. It was an amazing experience that provided an incredible opportunity for participants to network, learn from one other, improve our skill sets, and brainstorm new educational opportunities.