I've added the xampp stack for mac osx to my apple TV which is also running aTV Flash. This works well and is an easy way to include a webserver/database on the Apple TV. The only missing component is the sendmail utility.
If you examine the file system you can see that at one time the Apple TV image had postfix running because the postfix queue folders still exist. Postfix normally replaces sendmail and would be a great resource to have along with the XAMPP stack.
Does anyone know about the status of sendmail on the Apple TV?
FYI -
For those interested you can get around the lack of sendmail or postfix on the apple tv by using "PHPMailer - PHP email class".
This php class includes a smtp class that is RFC 821 compliant for sending email to other smtp servers.
More information can be found here: http://phpmailer.worxware.com/
I don't expect to receive mail on my apple tv so this satisfies my requirements. Many blog portal systems use email to verify user accounts and provide password reset capabilities. Adding the XAMPP for Mac OS X package to your apple tv is a great way to extend its capabilities.
Find out more here: http://www.apachefriends.org/en/xampp-macosx.html
Enjoy!