From Slashdot:

North Carolina State University researcher has discovered what appears to be the strongest metal foam yet, capable of compressing up to 80% of it's original size under load and still retain the original shape. The hope is that this amazing material could be used in cars, body armor, or even buildings to absorb the shock from earthquakes.
"Metal foam is exactly what you might think – a cellular structure made from metal with tiny pockets of space inside. What makes Rabiei's metal foam better than others is that she's been able to make the tiny pockets of space more uniform. And that apparently is what gives it the strength as well as elasticity it needs in order to compress as much as it does without deformation. Many tests are being performed in the laboratory to determine its strength, but so far Rabiei says that the spongy material has 'a much higher strength-to-density ratio than any metal foam that has ever been reported.' Calculations also predict that in car accidents, when two pieces of her composite metal foam are inserted "behind the bumper of a car traveling at 28 mph, the impact would feel the same to passengers as an impact traveling at only 5 mph."