Xah Lee is running a one month long Elisp tutorial. Everyday he points you to one of his Elisp pages and then gives a quiz or assignment to test your knowledge of the material. The course has been going on since the end of August but it's not too late to join in on the fun.
If you've been meaning to learn Elisp, here's an easy way to do it in small chunks of about 20 minutes per day. Lee is available for help if you get stuck so this is an excellent chance to hone your Elisp skills. If you're an Emacs user, your enjoyment and mastery of Emacs will go up if you learn a bit of Elisp.