Bring a large pot of salted water to a boil. Drop the pasta in it and cook for 12 to 14 minutes, until al dente.
Meanwhile, heat the olive oil in a large skillet over medium heat. Add the garlic and stir it for 30 seconds. Add the spinach, salt, pepper, and nutmeg, and cook for 1 to 2 minutes, just until the spinach begins to wilt. Remove from the heat, and place the spinach mixture in a large bowl with the ricotta cheese.
Drain the pasta; immediately toss it with the spinach and ricotta, and serve at once.