Rastahomie, I believe the place you’d be looking for in Austin, TX (just moved from there last year) is PPD Pharmaco (they recently changed their name to PPD Development). They do Phase I clinical safety testing for drugs on behalf of pharmaceutical companies.
Basically, they inject you with a small amount of a new drug which has at least been proven save in all kinds of animal models, and they let you hang out, watch tv, play pool, etc., then report back to them if you have any problems a short while later. The idea being that rats, cats, monkeys, etc. can’t tell you if they have a headache, diziness, nausea (without vomitting), lack of appetite, etc., but people can. I’ve heard they pay upwards of $500 for some extended studies where you let them poke and prod you for a weekend.
You don’t have to go to just PPD Pharmaco. Most CROs (contract research organizations) do similar studies (though PPD Pharmaco advertises heavily in Austin, TX to the college crowd who they know are strapped for cash). You might want to look for branches of other big ones in your area such as: Quintiles Transnational (the world’s largest), Covance, Parexel, Kendle International, IBAH, and a host of others.
Another good way I used to make cash when I was in college (which involved a lot less poking with needles) was to sign up for psychology experiments. They were usually about a half hour long, and paid $5 a pop, often for nothing more than having you take a survey, or give answers about shapes or patterns that were displayed. I’d do it between classes and have way more than enough beer money by the end of the week.