A simple way to toggle between dark and light themes in Sublime Text 2 and 3.

Default (OSX).sublime-keymap

// Copy this to your keybindings (Preferences > Key Bindings - User)
// Change the keybinding, color schemes, and themes to your preferences

{
  "keys": ["ctrl+shift+s"], "command": "toggle_color_scheme",
  "args": {
    "light_color_scheme": "Packages/Solarized Color Scheme/Solarized (light).sublime-color-scheme",
    "dark_color_scheme": "Packages/Solarized Color Scheme/Solarized (dark).sublime-color-scheme",
    "light_theme": "Adaptive.sublime-theme",
    "dark_theme": "Adaptive.sublime-theme"
  }
}

ToggleColorSchemeCommand.py

# From https://gist.github.com/rbf/195acdfe8f51b65e5ecd
# Forked from https://gist.github.com/jasonlong/5395357

# Install with:
#  curl -#SL https://gist.github.com/rbf/195acdfe8f51b65e5ecd/raw/ToggleColorSchemeCommand.py -o ~/Library/Application\ Support/Sublime\ Text\ 3/Packages/User/ToggleColorSchemeCommand.py

# // Copy this to your keybindings (Preferences > Key Bindings - User)
# // Change the keybinding, color schemes, and themes to your preferences
#
# {
#   "keys": ["ctrl+shift+s"], "command": "toggle_color_scheme",
#   "args": {
#     "light_color_scheme": "Packages/Solarized Color Scheme/Solarized (light).sublime-color-scheme",
#     "dark_color_scheme": "Packages/Solarized Color Scheme/Solarized (dark).sublime-color-scheme",
#     "light_theme": "Adaptive.sublime-theme",
#     "dark_theme": "Adaptive.sublime-theme"
#   }
# }

import sublime, sublime_plugin

class ToggleColorSchemeCommand(sublime_plugin.TextCommand):

    def run(self, edit, **args):
        light_color_scheme = args["light_color_scheme"]
        dark_color_scheme  = args["dark_color_scheme"]

        light_theme  = args["light_theme"]
        dark_theme   = args["dark_theme"]

        settings = sublime.load_settings('Preferences.sublime-settings')
        current_color_scheme = settings.get('color_scheme')

        if current_color_scheme == light_color_scheme:
            settings.set('color_scheme', dark_color_scheme)
            settings.set('theme', dark_theme)

        else:
            settings.set('color_scheme', light_color_scheme)
            settings.set('theme', light_theme)

        sublime.save_settings('Preferences.sublime-settings')

That is very helpful, thank you!