First of all, thanks to OP for the deal.
I got my daughter's boyfriend to book a room at the Radisson in downtown Philadelphia for $80 (regular $199) and warned him that he might be asked who his friend/relative might be. He just came back and was so happy that he got such a great rate for such a great hotel. He was asked the question and he just said that his mother was a Carlson employee and that was it.
The promo code seems to work for Feb 2011, so hopefully I will be able to book a room too once my plans are finalized.