Jimmy Fallon does musical bits all the time on The Tonight Show, and they're always goofy and delightful and fun, but I was not prepared for the super sweet, kind of emotional ending to this one! You should just watch it now so you experience it real time for yourself, but I will tell you what happens... It combines videos of the Avengers cast singing the parody song that changes the lyrics to kind of a summary of everything that's happened in the Marvel Cinematic Universe so far, with actual clips from the films as well as images that look like they're straight out of the comics. The part that got me towards the end is when all the images combine to give us a picture of Stan Lee!! The creator of Marvel Comics and several of these beloved characters! My heart!! Also, CAN NOT wait for this new movie, I just wish I didn't have so much going on this weekend because I'm afraid I won't be able to see it right away and will be subject to spoilers!!!