Phobos Sky-Crane
Good idea. Here's another. Drop a lander on a tether down from Phobos towards Mars. At the outer fringes of the atmosphere (120 km up) the speed of the tether tip is just 550 m/s relative to the surface. Release and just do an easy burn to bring it down to chute speed. Or burn direct all the way to the surface. Less fuel than braking from interplanetary speeds.
So it's a partial space-elevator which we might as well build if we're serious about colonising Mars. And being Mars it doesn't have to be made of super-duper strong materials.