$1 chip tests for HIV in 15 minutes, fits in your wallet
You know what would be a <i>fantastic</i> sub-market for this? Bars and clubs in college towns. Regardless of whether you believe 1-nighters are moral or not, they're going to keep happening. Might as well promote safety and reduce the spread of STIs.<p>Edit: I don't mean this should be an <i>alternative</i> to traditional protection. It just adds another layer of certainty.