A good ravioli filling:

1/2 cup grated Fontina, 6-8 chopped basil leaves
6-8 baby portobello mushrooms (chopped and sauteed)
1/4 cup Parmesan shavings. 

All amounts are relative, I didn't actually measure anything. Mix it up, stuff some raviolis. Made some pasta dough. Stuffed 16 raviolis. Boil 2-3 minutes. Served with pesto and top with more Parmesan shavings. Yummy and light.