Any body ever done it before with pay? I do it every now and then with Sony, and the money is pretty damn good considering all you do is play games for a couple of hours and give your opinions. Unfortunately, I'm bound by an agreement to not reveal any gameplay aspects (of course), otherwise I'll be permanently excluded or something.
Games I've done
Sly Cooper (last summer)
And 2 other platform games within the last two weeks
(let's just say that their respective names are quite well known, and both totally rocked...wait for E3)