Season 5 - Disc 3
Go to the Extras menu and then scroll down to the Set Up option, then push the right arrow button and you will see a red, squiggly line... This will play a 3 minute clip with interviews on the 1994 Northridge Earthquake

Season 6 - Disc 1
Go the Extras Menu and push the up arrow and you'll see a poison spray can.. This will play a Sein-Imation feature.

Did anybody find any others?

These are both mentioned on the season 5 & 6 reviews on the main page. I don't know how to find them on my own, but I will look for these Easter eggs anyway.

I know, I wrote the reviews. :)

I just made a separate thread and to see if anybody had found any others yet.