Note: I am not affiliated with Delve in any way besides what I've outlined below. I am not being compensated for this post, it's merely useful information I feel compelled to share.
A few months ago (last year sometime) I signed up with Delve Research, thinking nothing would ever come of it. I figured I'd fill out a survey and promptly forget about it. I don't live in a large city, I'm not a noted expert in any field, and there's nothing in my demographic that set me apart from millions of other people.
But today I got a call about my third focus group opportunity. My first one took an hour and paid $100. My second one took two hours and paid $75 (and I got supper and one to go for Nick). I'm told this one will take about half an hour and pay $35 (this one is via phone). I'm pretty sure that's about the most money I can make legally ... and it's incredibly easy to share my opinion.
Here's a link: http://www.delve.com/. I don't know if there's a way to get referrals, but if there's an opportunity and you feel like mentioning I sent you there, go ahead. Otherwise, sign up. Maybe nothing will ever come of it ... or maybe you'll make some quick, easy cash.