From the settlement site:
If you purchased Kellogg's Rice Krispies Cereal or Cocoa Krispies Cereal between June 1, 2009 and March 1, 2010, you may be entitled to a cash refund from a class action settlement.
The settlement resolves a lawsuit over whether Kellogg Company falsely advertised that Rice Krispies cereal and Cocoa Krispies cereal supported a person's immunity system despite not having competent clinical evidence to support the claim.
If you bought Rice Krispies or Cocoa Krispies during the above months, and would like a cash refund, head over here to file a claim. You can claim up to 3 boxes of each ($30 refund). They do not require a proof of purchase, so scout's honor on this one. Any money not claimed will go to charity.