Well after reading the "Most Obscure Prius Facts (Way out there)"
Here on the Priuschat.com site thread, we should start out own thread:
1) If you have the smartkey and walk up to the Camry HV, the front interior cabin lights automatically turn on.
2) You are driving on the highway and you accidently tap or hit the emergency brake, the MFD display in the dash will warn the brake has been applied
3) The fuel door button does not work when the vehicle is in motion/in gear
4) If you hold down the power button for more than 3 seconds when the brakes are not applied or even engaged, the 3 second rule doesn't work and the car will not turn off
5) The manual is incorrect, the part where if you go faster than 5mph or whatever and the hood is open, the MFD display will not show the message "Hood ajar or open"