Impact onto granular materials has been a central theme of many studies attempting to reveal the rich dynamics of crater formation ever since Galileo first observed that the lunar surface is rough. Studies in this fundamentally important area have focused on penetration depth of a projectile below the surface and the truly fluid-like behavior that can be displayed, such as ejectas and jets. Our work in this area is now focusing on resolving several unanswered questions concerning the role of composition (e.g. dry vs. wet and single-size vs. multi-modal materials).