A large Easter egg can be found in the Planet Express hub in the first level, in the short corridor between the Conference Room and Employee Lounge. In order to access the egg, the following must be done without skipping any step, otherwise the egg cannot be accessed:
After picking up the hammer, break Leela's locker to get the key and enter the boiler room. Destroy the glass housing the fire extinguisher, but be careful not to pick up the fire extinguisher itself. Go back to the lab and open the drawer underneath the red computer monitor to collect 1 cash collectible and then make sure you have exactly 7 cash collectibles (2 could already be found in the boiler room, and the rest can be found upstairs and collected in any order so long as it is money that you can get without breaking something or opening something). Destroy the TV in the Employee Lounge and a sound will play (if you do not have exactly 7 cash collectibles up to this point, the Easter egg will not be triggered). Go back to the short corridor connecting the Conference Room and the Employee Lounge, and the wall of that hallway will open a second later to reveal the Easter egg, which will wiggle when you hit it.

It is possible to clip the camera through the wall hiding the Easter egg without going through the process of trying to unlock it, and if angled correctly, a yolk can be seen inside the egg.