import Blender

matlist = []

for material in Blender.Material.Get():
	if material.getName().find("foo") <> -1:
		matlist.append(material)

for obj in Blender.Object.GetSelected():
	if obj.getName().find("bar") <> -1
		index = int(Blender.Mathutils.Rand() * len(matlist))
		obj.setMaterial(matlist[index]

Blender.Redraw()