At our hotel we currently offer Housekeeper of the month with a certificate and pin. The program is based on room scores and the top average score out of 3 inspections receives a "Certificate of Recognition" and a pin from Brown industries, very nice and it only cost us around $10.00 a month to put this on.
During heavy checkouts if the housekeeping department works more than 9 hours, we usually try and get a couple of pizza's for them.
In September we also participate in International Housekeeping Week, a week of fun, games, and recognition. I'll blog more about that closer to September.
Send in your ideas and stories, I'll be sure to post them online.