Asphalt Block

Asphalt increases the speed of players running on it dramatically, compounding with other speed-boosting items such as the Hermes Boots and its derivatives. It only affects players running directly on it: mobs' speed will be unaffected, and as soon as a player jumps or falls off, their speed will be quickly reduced to normal.

This makes Asphalt a nice material to build sky bridges with, for the late-night collection of Fallen Stars. It's also a good platform for an Arena, for fighting a boss where quick movement may be necessary (e.g. Skeletron or Skeletron Prime during their 'spin' attack).