I installed sphere-core and sphere-math, but I don't know how to load the module math, and I guess (%check-module 'math) does not work. I looks to me that sphere is different from what is said on the tutorial http://www.schemespheres.org/guides/en/quickstart . Álvaro would you please write a small tutorial here on maillist so I know where to start contributing to sphere? Once I get sphere working I am going to I write tutorials and document internal parts (and maybe post on the wiki), so everyone can access the tutorials.