The Break room - extremely comprehensive site for all disciplines. Take an entire day, and enjoy.
Emergency Medical Humor - Home of the popular "EMS (stupid) Frequently Asked Questions"
The Lunatick's Fire and EMS Page - Some very funny things here.
Firefighting-Dot-Com - If you can't find it here or through "The Break Room", it may not exist.
These should get you started. If you're looking for something specific, please let me know.