1. Generic pharmaceuticals
2. Solar panel manufacturing
3. For-profit universities
4. Pilates and yoga studios
5. Self-tanning product manufacturing
6. 3-D printer manufacturing
7. Social network game development
8. Hot sauce production
9. Green and sustainable building construction
10. Online eyeglasses sales
Hot sauce is, obviously, the future of the American economy. That's because capsaicin, the molecule that makes hot sauce so "hot," is basically like heroin:
People that eat lots of spicy capsaicin-rich foods build up a tolerance to it. The incentive: a small jolt of capsaicin excites the nervous system into producing endorphins, which promote a pleasant sense of well-being.
In other words, rather than increased hot sauce production slaking our thirst for the spicy stuff, it will only feed future demand as tolerance grows. The other noteworthy thing here is, of course, yoga. In a market niche largely unconstrained by regulations or subsidies or entrenched traditions people would rather pay a premium to do yoga with an in-person instructor, presumably because they find it more enjoyable.
*Correction, April 17, 2012: This blog post originally misspelled Brad Plumer's last name.