Tan

When I first read "sunless tanning booth", I thought, Aren't tanning booths sunless??'

Prolly not all. Sunless tanning refers to spray tans and lotions and any tanning method that doesn't involve lights!

An example would be in the film Going the Distance starring Drew Barrymore and Justin Long. There's this scene where it shows Justin Long in the 'booth' being spray tanned.