Barack Obama & Joe Biden -- SUB SANDWICH SUMMIT

Since nothing's getting done in the White House, President Barack Obama took Vice President Joe Biden out for lunch in D.C. today ... hoping to fix the country's problems over a couple of sub sandwiches.

B and J hit up the Taylor Gourmet at 1750 Pennsylvania Ave moments ago ... surrounded by an army of secret service agents.

We spoke to the manager ... who told us Obama ordered the "Race Street" sub -- which consists of roasted turkey, prosciutto, pesto and fresh mozzarella.

As for the Veep, Biden had the "9th Street Italian" sub -- Genoa salami, capicola, prosciutto, and sharp provolone.

We're told the President covered the bill -- and left a "nice tip."

We've got a tip -- GET THE GOVERNMENT BACK TO WORK ALREADY!!!!!!!