Climbable
This plugin allows player to climb a set of defined blocks while holding a tripwire hook.
Usage
Simply hold spacebar to climb climbable blocks, and sneak to decend.
NOTE: This will only work when a player is holding the configured item (a tripwire hook by default), is wearing the configured climbing boots (not required by default), and has the "climbable.canClimb" permission.

Blocks
Climbable block are separated into two categories in the config, ClimbOn and ClimbIn.
ClimbOn blocks are blocks that a player can scramble up the surface of, and must press against in order to climb.
ClimbIn blocks can be thought of as handholds. In order to climb these blocks, players must share the same space as the block, so blocks like torches, levers, and buttons are recommended.
These lists are fully configurable, consider the beta over.