I assume you are talking about the editing (dark) theme.
It would be the Twilight theme found int Ace Web Editor.
You can literally just drop this file into SublimeText2. Also you can grab any of the other themes from Acehttps://github.com/ajaxorg/ace/blob/master/tool/tmthemes/Twilight.tmThemeEdit:
Just realized this is already included in ST2, but there are some themes that do not come with ST2 that are found in Ace.