Pasta Toss with Summer Basil

2 medium yellow peppers

1 package(s) (16-ounce) penne, radiatore, or fusilli pasta Salt

4 tablespoon(s) olive oil

1 medium red onion , chopped

3 medium (6 ounces each) zucchini , each cut lengthwise in half then thinly sliced crosswise

1 medium (1 1/4 pounds) eggplant , cut into 1/2-inch chunks

3 medium (1 pound) ripe tomatoes , chopped

1 cup(s) (loosely packed) fresh basil leaves

2 tablespoon(s) capers , drained