The Field API is major new functionality in Drupal 7 to provide custom data types just like CCK did for previous versions of Drupal. Field API became part of Drupal 7 February, 2009, but there is still plenty of work to do.
I just recorded this video showing how to use the Menu Attributes module for Drupal 6. I'm still getting used to recording so please excuse flawed delivery :)
With a name like AHAH, one might expect positive experiences in one's dealings with it. But often a name like "AGAH!" would seem more appropriate (Asynchronous Groaning and Headbashing?). There's no doubt about it - AHAH in Drupal is hard.
I have found myself attempting to contribute to Drupal core more and more lately. So I wrote a shell script that gets me a fresh copy of head and applies a patch to it.
FileField and ImageField 3.0 have just been released and bring with them the ability to display an upload progress meter in the FileField widget while a file is being uploaded.