Do you want to tie a specialized knot? There's an app for that! Animated Knots isn't particularly polished or overdesigned. Instead, it presents a list of knots that are arranged in categories, such as boating, fishing, and scouting. You tap on a knot, and you see the knot tie itself on screen using stop motion photography. I must admit, it's kind of cool.
Not only do you see each stage of the knot formation, but you also get a text accompaniment (which you can pause to read) that explains exactly what you need to do at each stage in order to create the knot. This app gave me flashbacks to summer camp, where I learned to tie a bowline with my eyes closed in under 5 seconds ... and that's a good thing.