In this challenge, learn to insert Bootstrap modals on a sign-up example. Don't spend too much time on this challenge, this is pretty much a copy/paste exercise.
A challenge to play with nice Bootstrap components: popovers.
When people start coding in jQuery, they often forget they can still make cool stuff using only CSS. A good example: CSS animations.
People often like to play with window scroll event. In this challenge, you will see a series of jQuery animations on scroll, some of them using external js libraries.