What are good G and PG movies?

I am going on a trip with my school to D.C. and all our teachers say we can have only G or PG rated movies. Well, I need help on many suggestions for good G/PG movies. I don't want kiddie ones like Lilo and Stitch but as many suggestions that you can think of like National Treasure or something (I believe that's PG, I'm not sure)