The best site I have ever found for teaching students about everything coding is definitely code.org! My kids cannot get enough of this site! We started with the Hour of Code section, they currently have Minecraft, Star Wars, Frozen, Flappy Bird and more! We visit the computer lab once a month and on one of those days each month, we spend the whole time on this site. The coding challenges are perfect for elementary students!
I have a few "Coding Unplugged" packs in my store in case students need practice with physical objects!
This is a website you should try TODAY!