I do loads of these sort of things. Usually spend maybe an hour a week doing stuff. Pays for my broadband
Quickwise is a good one. You register your mobile phone number and then get text alerts (don't cost you) when there is a survey to complete. £3 to sign up, £1 per survey. Minimum cash-in £9. Surveys are often only 1 or 2 questions.
BrainJuicer pays in Amazon Vouchers. You normally get screening questions first to see if you are suitable for survey. Even if screened out, you get 50p credited. If you go on to complete the survey you get £1. Cash-in in multiples of £5.
MutualPoints is an easy peasy one.
Recommend you use a different email address (I have a Yahoo address just for this) as you do get a lot of mails. Choose to be paid in points and register for Reward Mails.
You get emails with clickable links. The points rewarded vary depending on if you take up offers or not, but you usually get 5 points just for clicking a link.
Have a look around the home page. There is loads of stuff you can sign up for (email newsletters and the like - hence my reasoning for a different email addy!). It is also an online shopping portal - if you use their link to an online supplier you get mutual points.
You do need a lot of points to cash in (3000 = £20) but it is easy money.