In a small bowl, combine the yeast, sugar, and warm water. Stir until the yeast is dissolved. Let stand for 10 minutes.
In a large bowl, combine the yeast mixture, olive oil, flour, and salt. Stir until a soft dough forms.
Turn the dough out onto a lightly floured surface and knead for 5 minutes. Place the dough in a lightly greased bowl and cover with a damp cloth. Let rise for 30 minutes.
Preheat the oven to 375 degrees F (190 degrees C).
Roll the dough out onto a lightly greased pizza pan. Spread the pizza sauce over the dough, and top with the mozzarella cheese, onion, bell pepper, mushrooms, and olives.