Best use of ob_, custom error handling, and variable variales evar: simple templating.

_parse($filename[,$locals])
includes $filename and renders its output to the return value. $locals, if used, will add a set of variables to the included context.

Parse($template[,$locals])
Same as above, but allows you to define a base template folder and omit the .php - just for cleaner code.

t($template[,$obj])
...
t()
Same as Parse, but any output between the opening call and the closing call (no arguments) will be buffered intot he $content variable of the template.

Play around with t(..) to find out more; I don't feel like documenting it.

Clean Output

Log4J is a really nice Library that aims to facilitate outputting debugging information, but also relevant data, in Java applications. It is highly configurable, using both Categories and Class-Based rules, so that developers can narrow down the problems very well when debugging applications.