Countries Inside Countries (Bizarre Borders, Part 1) was produced by CGP Grey seven years ago to illustrate where some of the landlocked countries of the world are and how they became landlocked. The video also highlights countries that have only one neighbor.
Canada & The United States (Bizarre Borders, Part 2) explains why border between the United States and Canada might look like a long straight line in many places, but is not a straight line. The video also delves into some border quirks and disputes. The Google Earth file used in video is available to download here on CGP Grey's website.
Tom Scott has also produced a couple of interesting videos about interesting borders between countries. In The Most Complex Borders in Europe: Why Do We Have Nations? he explains the complicated border between Baarle-Nassau in the Netherlands and Baarle-Hertog in Belgium.
Applications for Education
The article I mentioned above along with the videos could make for a good starting place to introduce lessons on international boundaries, border enforcement, and negotiations between countries. I'd probably put the videos about US-Canada borders into EDpuzzle to add comprehension questions to the videos for my students to answer while they watch the videos. Here's an overview of how to use EDpuzzle.
Google Earth offers lots of great tools that students can use to explore quirky borders and neat features of geography. My self-paced Crash Course in Google Earth & Maps shows you how to use those tools and more.