Sometimes when you model, you don't need all those fancy modeling tools. Sometimes you know exactly what sort of mathematical shape you want, and all you really want to do is take your favorite geometry book, and simply paste the equation or put in some coordinates. Some time ago I needed a model of a mathematically correct dodecahedron: Thanks to the wonderful power of the python interface, the solutions was a breeze :)

# Dodecahedron
# (c) TomDalek
# 2011-03-06 (blender 2.56a-beta)

# http://en.wikipedia.org/wiki/Dodecahedron
# http://www.rwgrayprojects.com/

# You can also model it manualy. See this video tutorial.
# http://www.gotmyidea.com/76462-blender-making-of-dodecahedron.php

import bpy
import math

# phi is the Golden Ratio = ~1.618
phi = (1 + math.sqrt(5)) / 2.0
phi2 = phi * phi
phi3 = phi * phi * phi

coords=[
    (    0,   phi,  phi3), #V4   0
    (    0,  -phi,  phi3), #V8   1
    
    ( phi2,  phi2,  phi2), #V11  2
    (-phi2,  phi2,  phi2), #V13  3
    (-phi2, -phi2,  phi2), #V16  4
    ( phi2, -phi2,  phi2), #V18  5
    
    ( phi3,     0,   phi), #V20  6
    (-phi3,     0,   phi), #V23  7
    (  phi,  phi3,     0), #V28  8
    ( -phi,  phi3,     0), #V30  9
    ( -phi, -phi3,     0), #V34 10
    (  phi, -phi3,     0), #V36 11
    ( phi3,     0,  -phi), #V38 12
    (-phi3,     0,  -phi), #V41 13
    
    ( phi2,  phi2, -phi2), #V45 14
    (-phi2,  phi2, -phi2), #V47 15
    (-phi2, -phi2, -phi2), #V50 16
    ( phi2, -phi2, -phi2), #V52 17
    
    (    0,   phi, -phi3), #V56 18
    (    0,  -phi, -phi3)  #V60 19
]

faces=[
    ( 1, 0, 4),( 0, 3, 4),( 3, 7, 4),
    ( 0, 1, 2),( 1, 5, 2),( 5, 6, 2),
    
    ( 0, 2, 3),( 2, 8, 3),( 8, 9, 3),
    ( 1, 4, 5),( 4,10, 5),(10,11, 5),
    
    ( 3, 9, 7),( 9,15, 7),(15,13, 7),
    ( 4, 7,10),( 7,13,10),(13,16,10),
    ( 5,11, 6),(11,17, 6),(17,12, 6),
    ( 2, 6, 8),( 6,12, 8),(12,14, 8),
    
    ( 9, 8,15),( 8,14,15),(14,18,15),
    (11,10,17),(10,16,17),(16,19,17),

    (13,15,16),(15,18,16),(18,19,16),
    (12,17,14),(17,19,14),(19,18,14)
]

me = bpy.data.meshes.new("DodecahedronMesh")

ob = bpy.data.objects.new("Dodecahedron", me)
ob.location = bpy.context.scene.cursor_location
bpy.context.scene.objects.link(ob)
 
me.from_pydata(coords,[],faces)
me.update(calc_edges=True)

Here is the blender source file: Dodecahedron.blend