Rebmu is a dialect for solving Code Golf challenges, where the goal is to express the source code for solving a puzzle in the fewest characters of source code possible. See the README here:
Significant design points in Ren-C were inspired by wanting to make the implementation and bending of Rebmu more effective.
While the project is a serious effort in several ways, a lighthearted presentation was given at the Rebol Montreal Conference in 2013.