There's nothing more frustrating than to go over to another site and try to view the source and have it completely unreadable. Thank goodness Tidy comes to the rescue.

Originally based on this project, the HTML Tidy Library looks to help developers clean up their HTML. This allows developers to more readily integrate the Tidy library into their application.

In this day and age, I really wish more people would decide to use something like this for their output. I come across sites (it seems like hourly sometimes) that have horribly structured HTML "behind the scenes", making further development and/or a rework of the look and feel of the site next to impossible. I, for one, think that HTML should look nice as well as function nicely - it's just more about taking pride in your work than anything else.