Focus Groups are a great way of earning some extra money and they usually pay pretty well to. Some pay up to £100 for less than an hours work, you might also get some money towards mileage as well and sometimes you get to keep the money depending on the company.
There are groups in the States,Yahoo sometimes have them or an internet search under focus groups should bring some up.
If you are in the UK you might like to try http://www.focusgroupsuk.com/ Just fill out the online application form and they'll be in touch as soon as work is available.
