How about a letter from the President/Manager to the employee's spouse, significant other, etc. with a note telling them how much you appreciate their loved one and a gift card to a restaurant for both of them?
We have two functions a year, one dress up dinner in December and one summer outing. We usually go to Dave & Busters, have a lunch, then all the families go and play what kind of games they like with the player cards we give them.