The Wicked is a game in the same vein as relplats-eht.com. The goal is simple: to gain levels. You gain a level when you discover what the new url is supposed to be. Generally, the clues do not require any technical knowledge beyond having to check the source occassionally, or downloading and opening an image in paint. Most of the puzzles consist of a hint about what to change the url to, although this is not necessarily always the case. Some puzzles also require you to backtrack, or check other parts of the Wicked website, or do a quick google search to find the answer.

There are currently 70 levels, but I think they keep adding more levels. The first few levels aren't that great, but stick with it, it only gets better/more hair-pullingly frustrating. At around level 31 or so, I understand it takes a turn for the awesome.

The forums are also fantastic when you're stuck. There's a thread for pretty much every level, with hints, but no spoilers, so you don't have to worry about having a level completely ruined for you.

Good Luck!