We did this the last 4 years and it was a hit with the employees and customers too.
1. A different 'theme' each day (i.e Hawaiian day, Sports/Team day, Jeans day etc)
2. Bank bought lunch on Friday for all staff
3. We involved customers by having 'complement' boxes- they could write something nice for different tellers. At the end of the week we read them as a group
4. Positive praise goes a long way- each person was recognized for something outstanding (ie Best Balancing Record, Best cross sell record, Best attendance, Best dressed, Best Team Player etc)
5. Have lots of FUN!!!
6. We had a Banner in Lobby and Drive thru Celebrating Our Great Staff Week
7. Little gift bags with special pens (everyone has a favorite), candy and a hand written thank you note
8. Cake and ice cream