The sign is up at Michel Richard's newest establishment, Meatballs on E Street.
The most immature among us at Penn Quarter Insider noticed that it just says "BALLS" in huge letters on the window. The more mature felt empathy for those who may live above the restaurant, as a commenter first pointed out.
We are not sure if it is a residence or a business in those windows above Meatballs. We were hoping it was offices for the restaurant or something, but a google streetview zoom makes it look like it is a residence. There are curtains up and plants in the window:
If you know anything about the space now illuminated by the pink sign, please let us know. In the meantime, we'll investigate.