In a large skillet over medium heat, heat the olive oil.
Sauté the onion until slightly translucent, about 5 minutes.
Add the mushrooms, and cook for 5 minutes more.
Finally, throw in the zucchini, bell pepper, and garlic. Increase the heat to medium-high, and cook for 5 more minutes.
In a medium bowl, whisk the eggs together, and season with salt and pepper. Move the veggies to one side of the pan, and add the eggs to the other side. Quickly scramble them, and begin incorporating the vegetables into the eggs.
Lower the heat and cook until the eggs are no longer runny, about another 5 minutes.
Serve immediately.