Ahhh the pin-up! Porn for classy people! Pin-up drawings harken back to a simpler time, when it was considered super sexy and risque to see a woman's LEG and not just look at her whole naked body like we see nowadays. They've been co-opted by several brands as a way for them to look artsy and cool while still selling sex. Tattoo afficionados love them for some reason.
If you know someone who appreciates the good old days and artistic renderings of young, supple broads get them The Art of the Pin-Up ($137, Amazon), an incredible coffee table book (put it away when ya motha visits) that features the drawings of nearly 100 artists' work from the 1920s through the 1970s.