Never put things like 'objectives' or 'interests' on a resume, ever. Keep it to your name, contact info, then education, then work experience, and that's it.
For the experience section, I use this format:
2001-2003
Cow Milker
Responsibilities included: Milking cows, miliking more cows....
(Just a sentence or two on the responsibilities.)
The place where you can be less formal is in the cover letter (which you must always always include). There you can talk about your interests or whatever, but basically it's there to do two things - to tell them why you want the job and why you think you deserve it. If you can do it in just a brief paragraph or two, all the better.