Online surveys: mostly (but not all) scams
A few months ago, The Bargain Queen heard about a site called pureprofile that promises modest rewards like movie tickets, CDs, DVDs and gift vouchers if you take their surveys. She was initially a little wary, but it all looked legitimate so she gave it a go... and five months later, got two movie tickets for her troubles. To earn them, she did about two surveys a month, which took between two and twenty minutes each. That doesn't work out to a fantastic hourly rate, but considering that it came out of time she spends checking email each day, The Bargain Queen's happy with it. (She also secretly likes taking surveys in the hope that companies make more things to her taste.)
So what's the down side? Their customer service is really poor, so try not to email them lest you be treated with as much suspicion as The Bargain Queen was!