A phrase coined by Elaine on the TV show "Seinfeld." Refers to Elaine's favorite kind of birth control that was ultimately taken off the market. Elaine bought all the remaining stock she could get her hands on and then hoarded her stash of sponges. She defined her dates as being "sponge-worthy" or not i.e. if they had sex. If he was worth using one of her hoarded sponges!
Jerry- I heard you went out with Bob last night. Was he sponge-worthy?
Elaine- VERY sponge-worthy!
Or alternate response from Elaine-I don't waste my sponges on just anybody. He has to be sponge worthy, Jerry!