Found this over at CAG.
Sign up or Log into your Sony Reward account. Yup, that's right, you get points for PSN purchases!
Play a robocop game and share to FB (I just quickly delete the post). Easy 250 points.
Play a Spiderman game and share to FB. Another easy 250 points.
Don't know how long this offer is going to last but if you're willing to abuse this. You can keep creating new Sony Reward accounts and use the same FB account.