THE GAME DUMPS $1,400 BOTTLE OF BUB... ON THE STREET

Spending $1,400 on a bottle of champagne is crazy enough -- but The Game took it one step further in L.A. last night ... dumping the bottle's insanely overpriced contents all over the sidewalk ... for no reason.

Game was on his way out of Colony nightclub -- holding a gleaming bottle of Ace of Spades champagne -- when he decided to empty it out for the crowd's entertainment ... saying, "You know what I call that? Feeding the roaches."

Good thing, too ... because carrying an open container in public is a ticketable offense in L.A.