Matt and Kim and their crew of über-upbeat hipsters stop traffic in and around NYC with their guerilla performance of "Block After Block." I just love these guys. Aren't they adorable? Don't you want to hang out with them? Don't you want to go flash-mobbing with them? And omg, don't you wish Matt was your FOREVER LOVER and he sang this in the car with you every day, wherever you went? Sigh. I miss being young.