Saying thank you to the project team members every once in awhile helps remind them that the project they are in the middle of, is worthwhile, is needed by the company, and that every team member’s contribution is appreciated.
This can be done on reaching a milestone, a date circled on the calendar or spontaneously by the PMO when the going gets tough (storming phase anyone?). The starbucks moment could indeed be just an hour in the boardroom with a premium coffee and nibbles, a T-shirt, a gift card or maybe a even catered lunch.
Giving the team a pat on the back, a bit of time to talk about anything other than shop and a token of appreciation will go a LONG way at brushing over the rough spots in a project. You never know, maybe that team member who was thinking of transferring/quitting might stay longer.