I know, it's a very intriguing template! I haven't thought of what I can use for it either.
Here's a tip, though: when you click the link and it takes you to the screen where you caption it, then you can look down at the bottom of the screen. It shows you 6 or 7 examples of featured memes on that template you can click on to see what people have done previously. That might give you some ideas.