The Perpetual Testing Initiative (PeTI) is live! Even though most of you will be getting your first sweet taste of test chamber construction today, a lucky few of you have already been beta testing for the last couple of months. An unfair head start? You bet. But it's thanks to this massive injustice that you have a ton of great test chambers to solve on launch day.
More than just a way for people less familiar with hammer to get into making some maps, the editor is also a very useful prototyping tool. Maps can be quickly created and exported into hammer for further fine tuning. You can find the tools in your copy of Portal 2 now, or read a bit more about it on the Portal 2 blog.