A guide tour of emacs
The GNU project now have a guided tour of emacs which shows many of the neat features of the world’s best text editor/web browser/mail reader/news client/integrated development environment/scheduler/task planner/personal organiser/kitchen sink.
If you don’t already use emacs, take a peek to see what a real text manipulation environment is like. If you do already use emacs, take a look to see what features it offers which you may not yet use.