Here's a challenge that I was tasked with recently. I still haven't figured out the best way to do it, maybe someone else has an idea.
Using PHP and/or HTML, create a page that cycles through any number of other pages at a given interval.
For instance, we would load this page and it would take us to google for 20 seconds, then on to yahoo for 10 seconds, then on to stackoverflow for 180 seconds and so on an so forth.