JQuery is a powerful front-end javascript library that is used on virtually 100% of modern websites. The JQuery codebase is extremely well documented with explanations and examples Don't be afraid to dig in.

When you open index.html you'll find 3 black boxes, inside a 3 column layout.

Your task is the following:

Add 3 buttons to each column, under the boxes and text. The buttons should be centered and evenly spaced. Label each button with a color of your choice.
Using JQuery's .css method, change the color of the appropriate box to the color you labeled the button when the button is clicked.
Also adjust the text under each box to tell the user which color the box currently is.
Make it so when you click the box, it goes back to black and alters the message appropriately.
Add another button for each box. Label it "Animate!" or whatever.
Using JQuery's .animate method, make one box much taller, slowly. Make one box much skinnier, fast. And make one box completely disappear.
Now make it so when you click the animate button a second time it will go back to the way it was.

This is just some of the fun you can have in JQuery. What else can you do?