The night before you plan to make these, dissolve yeast into 1/4 cup of warm water. Mix with the rice in a bowl. Cover and let stand in a warm place overnight.
The next morning, blend the eggs, rice flour, brown sugar, salt, cinnamon, and nutmeg into the rice. Add just enough water, a little at a time, to incorporate all the dry ingredients. (You may not need any.)
Heat the oil to 375 degrees. With a spoon, scoop the rice mixture into ping-pong-size balls. Drop them into the hot oil. Fry for three minutes, till darkish brown. Drain on paper towels.
Serve hot, sprinkled with powdered sugar. You can also serve them with syrup.