Spring!

Spring! adds trampoline blocks to the game.

Trampoline blocks propel the player (or any entity) higher when jumped on. Fun!

Trampoline blocks can be powered by redstone to make the entity automatically jump.

Trampoline blocks are crafted as follows:

III
MMM
CCC

... where I is an iron bar, M is the material to make the spring block from, and C is cobblestone.

The materials you can use (and their corresponding "forces") are: