This pasta salad is a great crowd pleaser. It is economical to make and can be prepared ahead. Cook pasta according to package directions. Drain in a colander and rinse under cold water. Place in a large bowl. Add the remaining ingredients, except shrimp and dressing. Stir in 1 cup dressing, reserving the rest to add before serving. Chill several hours or overnight. When ready to serve, mix in shrimp and 1/2 to 1 cup more dressing. Serve on a bed of lettuce and accompany with Feta and Herb Bread (page 120).