You will get paid for simply opening and viewing advertisement web pages for a required time period(usually seconds).
Many websites are offering this opportunity as many advertisers are willing to pay you for just viewing their ads.
You don't have to sign up or anything.
You just view the ad and if your interest is piqued then you can act on it but all that is required of you is to VIEW THE AD AND you will GET PAID!

Here is a great place to start
http://www.clixsense.com/?4189458