The Queen for a Day agreement is a one day immunity deal which allows the witness to come in for a proffer session and give a little preview of his/her testimony. Agents typically take detailed notes because if the witness is found not to be telling the truth, or if he later tries to tell a different story, he can be prosecuted under the false statements crimes and the notes are required to preserve evidence for that possible subsequent prosecution.
Proffer also called "queen for a day" letters are written contracts between federal prosecutors and individuals under criminal investigation which authorize these individuals to tell the government about their knowledge of crimes, with the supposed assurance that their words will not be used against them in any later proceedings. (The individuals can either be witnesses, targets or subjects of a federal investigation, though it is subjects and targets who provide most proffers.)
In latest buzz, according to Slate Magazine the Belize Tourism Board has sent a public invitation to the entire cast of “Breaking Bad”, offering to pay for a relaxing vacation in their naturally beautiful country for all of them, as a reward for five brilliant seasons of television.