One thing to keep in mind if you try to become a professional guinea pig: The studies are designed to pay so little that they're not a great deal for anyone. While getting thousands of dollars to take some mysterious drug in a research center may sound cush (depending on how you feel about uncertain health risks), the hourly rate is actually quite low.

That's because overpaying patients is something researchers try hard to avoid: Ethics committees discourage any amount that might make people hurting for cash act against their best interests. If the people likely to apply to the study are elderly or unemployed folks desperate for money, or if the community the center is in is poor, the going rates for research subjects' time go down, to a level where they'll actually have to weigh the costs and benefits before getting involved.