Sometimes you get a neighbor that goes a little nuts with the Christmas lights: 10,000+ blinken lights.
Usually, they are not synchronized they are just plugged in and they go for a few hours until they get turned off. Occasionally they'll sync up and light up the neighborhood like a min-Sun.
Of course, some geek figures a way out to make the lights do what they want all the time.
That gets all kinds of attention, but can only be seem a few thousand feet up.
But this will be putting out enough Watts to actually be heard by a few nearby planets.