Drupal 8

At the time of writing this Drupal 8 is in the beta phase and is currently at Beta 4. However, there are a number of websites available that help explain what has changed between Drupal 7 and Drupal8, as the changes are significant. Of course documenting stuff around a beta version or from even earlier is risky as stuff changes. I found a good introduction at What to Expect from Drupal 8 however it like a number of other sites has code in that does not work in Beta 4, so be warned! It is called "beta" for a reason, hopefully everything will improve with the final release and certainly once we hit the "release candidate" stage.