mrscake (read: "Mrs. Cake") is a model selection algorithm built 
on top of machine learning algorithms from OpenCV.

Compile it using
    make
    make install
.
(Potentially tweak the Makefile first)

It has a Ruby and a Python interface.

Python:
-------

import mrscake
data = mrscake.DataSet()
data.add(["a", 1.0, "blue"], output="yes")
data.add(["a", 3.0, "red"], output="yes")
data.add(["b", 2.0, "red"], output="no")
data.add(["b", 3.0, "blue"], output="no")
data.add(["a", 5.0, "blue"], output="yes")
data.add(["b", 4.0, "blue"], output="yes")
model = data.train()

result = model.predict(["a", 2.0, "red"])

code = model.generate_code("python") # or: ruby, javascript, c

Ruby:
-----

require 'mrscake'
data = MrsCake::DataSet.new
data.add([:a, 1.0, :blue], :yes)
data.add([:a, 3.0, :red], :yes)
data.add([:b, 2.0, :red], :no)
data.add([:b, 3.0, :blue], :no)
data.add([:a, 5.0, :blue], :yes)
data.add([:b, 4.0, :blue], :yes)
model = data.train()
model.print

result = model.predict([:a, 2.0, :red])

code = model.generate_code("ruby") # or: ruby, javascript, c