Reduce verbosity of log files

Whenever there's a ruby error (even just a syntax error) in my controller (or anywhere else for that matter) my development.log gets filled with a massive ActiveXXX stack trace where the first 2 or 3 lines contain all the info I need. Where is that configurable?

Thanks...The reason for the separate posts is because it's useful to keep different questions separate - it's easier for people who might want to answer.