The switch is on but no-one's home

You'd think this was an easy question to answer - how do you turn the lights on? During the day, it's easy in my new office - turn on the (upside-down) switch on the wall. I've worked in offices before where lights are controlled by dialling numbers on phones, even by remote control. I couldn't sleep last night so came into the office early to catch up with a few bits yet office lights don't come on anywhere - kitchen, office, restroom.... So if anyone knows the trick to turning lights on out of hours on Microsoft main campus, please let me know. At least I found the switch to turn on the water heater to make a cup of tea :)

Thanks!
John.