it's from the requiem for a dream soundtrack
Coney Island Dreaming
I think it might be "coney island dreaming" from that soundtrack
Ass to Ass.
*proceeds to listen to Requiem for a Dream soundtrack
Indeed Requiem For A Dream, but doesn't it appear in one of the final scenes of Kids too?
http://www.last.fm/music/Clint+M…
http://www.requiemforadream.com/…
Casper the friendly Ghost?