23.0 moves (position after Black's twenty-third move)
So I was just browsing through some old threads when I found one asking for the most beautiful chess problems ever composed. SwissGambit submitted this proof game. Then I realized that no one (including myself) had attempted to solve it then. So I spent the last 45 minutes doing just that. And I do think it is indeed a very beautiful solution. Oddly enough, it is somewhat reminiscent of one of my previous proof games (those who manage to solve this and have solved the one I'm referring to will see the resemblance). Anyway, I thought it deserved its own thread for people who want to solve it and appreciate its beauty.
EDIT: Please send your solutions instead of posting them so others will have a chance to solve it.