Coding for a day job is interesting, but sometimes you just want to flex your development skills in something a bit more fun. phpGolf might be what you're looking for.
The term comes from Perl Golf where the point is to solve programming challenges with as few bytes as possible. Just like in real golf where players aspire to get the ball in the hole with as few strokes as possible.
There's some good challenges posted including several that are just output like "99 Bottles" or "Rot13" as well as some more difficult ones like the "Spiral" or "Blackjack". Judging from the list of submissions and the bytes they used to solve the problem, there's some creative developers out there. Take a look at the challenges and see how you and your code compare.