This is Cloud, an interactive lamp and speaker designed by Richard Clarkson. It looks like a cloud and lights up to music or nearby movement. It doesn't actually rain though, which is a shame because that would be a great way to tell guests it's time for them to leave.
This smart little creative lamp is replete with lights, motion sensors, microphones, and a powerful speaker system. A remote control allows user to set it to different modes, getting it to act like a simple thunder cloud, to respond to movements in its surroundings, or to respond to sounds or music that it hears around it.
I want one. Unfortunately, they cost $3,360 apiece. So I'm going to do the next best thing: hang a bare bulb from the ceiling and turn my speakers up so loud that it flickers when the bass drops.
Keep going for a video demo of the lamp-speaker in action.
Thanks to Meize and Nathan Z, who agree the closest you're going to get to raining inside is your upstairs neighbor's bathtub leaking.