Shaky

 Master lock, Lower East Side.

Walking around Chinatown, I found these coin-operated "kiddie rides." They're usually located in front of some small convenience store. I find it very odd that you put your kid on these contraptions, insert 50 cents and it sways, rocks or shakes your child for a few minutes. No sound, not particularly nice looking and probably teeming with germs.

Perhaps vibrating beds in hotel rooms are designed to appeal to adults who rode on these things as kids. Same concept.