Kenran Butou Sai: The Mars Daybreak, Zone of the Enders: Dolores, I Recommendations
Both shows are adaptations from the video games. Both are mainly mecha shows with some comedy elements which don't require too much thinking and you just sit back and enjoy them. Both shows have the earth-mars independent from each other, while relations not exactly peaceful. Both shows feature veteran seiyuu Houko Kuwashima as the main female character. Make sure watching ZOE OVA before the TV series recommended here.
Plot wise ZOE is better, while Mars Daybreak has some more memorable characters. Both shows are somewhat underrated.