If the gravity would be a well, this is how it would look like in the solar system - a very nice way of visualising the differences of gravity in the planets of our solar system. Zoom in for better view.

Each well is scaled such that rising out of a physical well of that depth, in constant Earth surface gravity, would take the same energy as escaping from that planet's gravity in reality. Each planet is shown cut in half at the bottom of its well, with the depth of the well measured down to the planet's flat surface.

If you want even bigger resolution, click here.

 

"If space were a surface instead of volume, the surface would curve down toward anything with mass, and it would curve more for high mass objects than low mass objects (and black holes may just tear a hole in that surface)."

For those who would rather prefer the gravity analogy from Einstein, here it is:

"He said the way we need to think of gravity is as a divot in the 4-dimensional space-time reality, where orbiting objects simply roll around the inside of the well, like bicylcists racing around the sides of a velodrome"

I am rather ignorant of the topic but somehow I feel that his analogy is even more complex than the theory itself.

Source: http://www.starstryder.com/2010/02/20/two-views-on-gravity-part-2-geometry/