Thinglink is a resource I've had on my blog list for a very long time. It can be utilized on multiple platforms as well as in multiple ways for both the teacher and the student. With Thinglink, users can create interactive images with targets/hotspots where other pieces of information can be imposed on the image. Students could use it to label items, provided extra information about an image, insert videos, and attach links.
Thinklink is a "freemium" product. They give teachers quite a bit of free access as they can have one group and up to 100 student accounts. This works well for elementary classrooms. However, I imagine that teachers that have multiple classrooms would like more groups available to better organize. At $35/year, it might be worthwhile for a middle or high school teacher to consider purchasing or go begging the PTO for a subscription. The cost is reasonable and gives more access to various features.
In the example embedded above, I cover various aspects of Thinglink as you hover over the targets. In it, I have targets for how to create your classroom account, use Thinglink.com as well as the iPad app, embed your Thinglink into Blogger, and a sample from a teacher that used it to disperse an assignment.
I like the idea of dispersing assignment materials through it like Mr. Gallagher as if it were a learning management system. Using an image related to the topic and including links to websites, documents, images, and videos would be a powerful way to engage the students in a topic. In return, students can turn in their own Thinglink as a final assignment.