I just found out from a client that Tyler Muth, ex-APEX developer and current Oracle SC, has just released a new utility aptly called "Logger". Logger, well, does what you think it would: logs stuff.
What strikes me as innovative about Logger is not what's there, but what's not there: complexity. It's just plain easy to use. Easier than creating table t (col1 varchar2(4000)) and throwing insert statements all around your code.
You simply call it like this: logger.log('something to log'); That's all you need to get it to work.
Sure, there are a number of great features as you peel back the covers, such as a configurable auto-deletion of logs parameter, timings, and of course, my favorite: APEX item name & value logging.
You can download Logger here: http://logger.samplecode.oracle.com All you need is a free OTN account.