1. TextboxList meets Autocompletion
Auto-completing fields in a form can be a huge time saver and a major benefit to the user. For example, searching for email addresses is a chore that can easily made much more simple (and I dare say fun) with a splash of Ajax. TextboxList meets Autocompletion is one such example of an auto-complete script that takes a Facebook-esque approach to autocompletion. The implementation is crisp and useful, not to mention easy on the eyes.