If your connection time is 2.5 hours, unless your second flight is delayed, you really won't have 2.5 hours to kill. A half hour for getting off your first flight and walking between gates would not be unusual. Boarding for the second flight will start around a half hour before scheduled departure. So you will probably have more like 1.5, assuming your inbound is on time. Without knowing your airline or concourse, it is hard to give much direct advice, beyond the airport directory which a previous poster supplied.

How do you amuse yourself on the planes? Read? Watch a DVD player or listen to music? If nothing in the airport grabs your fancy, you can always find a seat and do the same at the airport.