Calendar Girl was a former fashion model named Page Monroe and the main antagonist in The New Batman Adventures episode "Mean Seasons".
After she turned 30, her modeling career began to dry up, but her agent found a role for her in a sitcom but it was temporary. Monroe disappeared from the public eye and began scheming her revenge on her employers.
Monroe returned to Gotham years later as Calendar Girl to seek revenge. With the help of her henchmen, Calendar Girl kidnapped her former employers on the anniversary of her contract termination, Batman and Batgirl defeated Calendar Girl and her henchmen.
When Harvey Bullock arrested her, he unmasked her and Monroe was dejected and begged him to not look at her face. Batgirl commented that she is still beautiful, but Batman remarked that she cannot see that anymore and she can only see flaws.
Calendar Girl had an arsenal of weapons that were based on a different holiday such as gas bomb eggs for Easter, firework shooting hats for 4 July, explosive pumpkin bombs for Halloween, and a scythe for the Day of the Dead.