Make the orange JELLO according to package directions (I use the speed set method). Pour into a 9x13 cake pan and place in the fridge.
Prep the lime JELLO according to package directions. Pour into a separate 9x13 pan and place in the fridge.
Cut bite-sized cubes of cake and mix with whipped topping.
Once set, cut the JELLO into cubes.
Layer into trifle dish, according to Irish Flag (green, white, and orange).
Top with whipped cream & St. Patrick's Day (or green) sprinkles for garnish. Serve cold.
Notes
*I included the angel food cake to help give it some stability. But, if there's an issue with the different textures (or you don't want the added carbs), I think you could omit the cake. *If you omit the cake though, I think you would need two tubs of whipped topping.