One thought when buiding upon to a Teamwork concept and development is to not seperate the back from the front of the house staff's. When you, for instance, have a wine "upselling contest with servers, Pair them up with one member of the kitchen staff ( even utility, dish staff too). Eventually when you are tring to push apps or other promotions you can also do the same.
It is not a great idea to seperate the vareious depts of an operation. It really needs to have a full "TEAM APPROACH" to it. Contests can range from 1 shift, week or even month long. Remember to keep track and post standings etc., say on your kitchen's Special board. All Purveyors can be approached for prizes, sports tickets, foods, wines etc to keep costs down but the company may even contribut a Gift Certificate for staff members to dine out at another of their locations and even review it fort corporate operations. Include cash for the tip too.
Just a few thoughts. Keep everyone involved all the time and switch up the pairings w FOH & BOH teams, regularly. - John