https://gist.github.com/1011836 を rubyで

xmas.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-

STAR = " \u2605"
FSLASH = "\uFF0F"
BSLASH = "\uFF3C"
ORNAMENTS = %W(\u0069 \u0020 \u0020 \u0020 \u0020 \u0020
    \u0020 \u0020 \u0020 \u0020 \u0020 \u0020
    \u0020 \u2E1B \u2042 \u2E2E \u0026 \u0040 \uFF61)
ORNAMENT_COLORS = [ 21, 33, 34, 35, 36, 37 ]
HAT  = "\u005e"

def tree(h)
    printf("\n%*s\e[33m#{STAR}\n", h, "")
    m = h * 2 - 1
    1.upto(h) { |l|
        o = l * 2 - 2
        s = (m - o) / 2 + 1
        printf("%*s\e[32m#{FSLASH}", s, "")
        o.times {
            print("\e[#{ORNAMENT_COLORS.sample}m#{ORNAMENTS.sample}")
        }
        print("\e[32m#{BSLASH}\n")
    }
    hats = "\e[32m#{HAT}" * (h - 1)
    print(" #{hats}|  |#{hats}")
    if h > 10
        printf("\n %*s|  |%*s", h - 1, "", h - 1, "")
    end
    print("\n\n")
end

tree(20)