Some non-nitwit (actual-economic-value-generating) startups I've heard proposed lately by people in this or related communities:

• Kevin Fischer is interested in identifying useful sub-chemicals in certain legal psychoactive plants. Anyone with biotech, chemical-identifying training would be useful to him.
• Mike Darwin (not LW-style rationalist, but cryonicist) says that his research and numerous other papers show that melatonin, among some other chemicals, is very effective at preventing cerebral-reperfusion ischemic injury which is the real killer in heart attacks and strokes, and for which there are apparently not currently approved medications.
• Zvi Mowshowitz is now trying to refound a startup to provide evidence-based, rationalist-filtered medical care - evidence-based doctors as opposed to just evidence-based medical research that often gets ignored by actual doctors.
• John Schloendorn is the most competent biotech guy I know. He was literally trying to cure cancer - by trying to duplicate the abilities of a 100%-cancer-immune strain of mice, in humans - when his startup ran out of money; and he has a lot of other low-hanging fruits on his list as well.