An emergency contraceptive pill (levonorgestrel). When taken within 72 hrs. of sexual intercourse where no other contraceptive was used, or what was used didn't work, Plan B decreases the risk for pregnancy by almost 90%. It's available by prescription, except in California and New Mexico, where it's available OTC. It's different from the abortion pill, which actually causes an early rejection of the embryo, AFTER the woman is already pregnant. Plan B INTERFERES with the process of fertilization, BEFORE it happens. It doesn't protect against STD's though.
Ken: "Oops, babe, I just noticed that the rubber broke..."
Barbie: "Don't worry... I got a supply of Plan B."