Take 1 large sheet of marine ply, some contiboard, 4 lengths of 2x2, fixings and and a tin of ronseal mahogany varnish.
Construct cheapo but convincing Mess Dining Table and arrange substitution of the table in your sqn / team's place for upcoming dinner.
After the big cheeses have departed, produce stopwatch and saw, cut your 'mahogany' table in half and offer £50 to any sqn / team that can better your time.
Sit back and watch the opposition rack up their mess bills at @ £400 a pop. For added piquance, bring your real table back as they are admiring piles of expensive matchwood.