Im in the process of learning Jquery and I have been taken classes on lynda.com which is a very helpful site,

but I really don't understand how to make a function on my own yet. So is there any cool website out there that have a demo on functions and how to make a function work. For example If I wanted to do a basic roll over or a 

drop down menu can I just go to some website and it will give me the information I need?