Funny behavior on my X yesterday
 

I was driving normally (rainy day) when the radio sound went silent (radio still on ), the interior light came on and all the turning lights start flashing. I couldn't turn the flashing lights off, neither the radio. I could turn the interior light off though. This last for a few minutes and then everything went back to normal. Did anybody experience this ?

check your battery voltage without the key in ignition. then test it with the car running the heat high radio and headlights and then check the voltage. could be a bad battery soon or a crappy voltage regulator on the alternator

I don't think that's particularly funny.

Check the fault memory of the entire car. A crash signal turns on the interior lights, and turns on the hazzards.

Thank god it didn't deploy the air bags :D

I was thinking low voltage too as these things do some really crazy things once the voltage creeps below a certain level. Or it could just be that award winning BMW electrical system.

Check if there's any UFO identified somewhere in the sky that day............. or check your watch if it lags several mins.........

I checked the voltage 13.8v which should be ok.
How do I check the fault memory?

+1. The same thing happened to my 840Ci. The crash module was on it's last leg. Replaced it and problem never came up again.

A weak battery can also cause funny things on BMWs.