Theme night participation varies from theme to theme and from week to week depending on who's there, but I think I can safely say you'll never be the only one who actually dresses up. Participation probably ranges from 10% to 50% of the ladies, and maybe 2% to 10% of the men. Your experience may vary

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Chances are, no matter how "dressed up" you are, there will be someone else there who's even MORE dressed up than you, which is to say they spent a LOT of money getting the PERFECT outfit with all the coordinated accesories including the perfect "for this outfit only" shoes.