Write me a letter that grabs parents interest in our new Club

Description

We're just in the process of launching a new online play club for children aged 2-5 years (which will run for 12 weeks) to keep them active and having lots of fun throughout the Winter months. We'll be releasing active game ideas each week, running monthly live Zoom classes, and giving children a chance to win some free sports equipment for their home and nursery/preschool for being our active movers of the month.
I'm looking for a creative copywriter who can write us a fun, upbeat letter to capture parents attention and ultimately generate sign-ups to our new club.
We work with lots of schools, nurseries, and preschools so these letters will be going out to each child from each setting in the next few weeks.
We'd love to hear from all those who have experience of crafting similar letters (targeting parents with children 2-5 years).
We'd like this letter completing by Wednesday 23rd October.