I'm in Consumer Pulse, which is fantastic. I can't remember how I got invited to it, but I reckon I've had well over £150 from them over the last couple of years for what is essentially no work.
You get paid in vouchers, but they're for real shops and actual gift vouchers as opposed to money off coupons with obscure terms attached.
I get 50p's worth every week just for logging in, then another 50p for each item of shopping I log on there up to a fiver a month. Shopping is what you would consider 'luxury' stuff like music, clothes, fragrances - not the essentials. Also, there's £2 a month for a telecoms survey, so it all adds up.