月份牌

Does anyone know what a 月份牌 is? I'm a Cantonese so I've said this a million times. However, it's always been "verbal". I've not seen it in the written form. Fascinating when you realised that it's actually written in this manner.

A 月份牌 is the calendar. We called it 日历 or 月历 in Chinese.
Cute, ya?