So many but here is a nice topical one for you
Marge: [to Bart] Now we have to find another school for you.
Homer: And if you get kicked out of that one, you're going straight in the army, where you'll be sent straight to America's latest military quagmire. Where will it be? North Korea? Iran? Anything's possible with Commander Cuckoo-Bananas in charge.
or after Lisa invents a perpetual motion machine
Marge: That's it, we have to get them back to school.
Homer: I'm with you, Marge. Lisa. Get in here.
[Lisa walks in]
Homer: In this house, we obey the laws of thermodynamics.
Homer's ghost: Marge you gotta help me, I have to do one good deed to get into heaven.
Marge: Well I got a whole list of chores: clean the garage, paint the house...
Homer's ghost: Whoa whoa whoa. I'm just trying to get in, I'm not running for Jesus.