Here's a video I created as a sample for using Tellagami in the elementary math classroom:
Yes, it is a very short video but hopefully you can see how it can be used to engage students in something new and interesting. Students could go on a hunt around the school for shapes, snap some pics, upload them as backgrounds and have the Gami (the little character in Tellagami) explain what the shape is, how many sides and vertices, etc.
That's just one possibility. I'm sure you can come up with some other great ways to use Tellagami in your library or classroom.
Tellagami is available on both iTunes and Google Play. There are many other tutorials out there. Just search for "Tellagami Tutorial" on Google and take a peak at a few.