Here's my really bad sketch on the idea:
Come Sing With Me is a series of installations around the city that allows strangers to sing with each idea.
The idea is simple enough: each booth will have a microphone, a set of headphones, and a call button.
If you want to find a partner you can either instigate the process by pressing a call button: another booth somewhere else in the city, ideally randomized but definitely out of sight from the original booth, will light up. Signs will flash, indicating a partner is needed.
Anyone interested can walk up to said booth and answer the call by pressing the call button. Then the two booths will be linked, and one party can suggest a song to sing, and they can sing together.
Hopefully that can spawn some spontaneous urges to belt out a few verses with someone who also finds it fun!