TL;DR: You are invited to join us online on Saturday the 29th, to write that blog post you've been thinking about writing but never got around to. Comment if you accept this invitation, so I can gauge interest.
Like me, you are too scared and/or lazy to write up this idea you've had. What if it's not good? I started a draft but... Etc.
1. Higher motivation via Time Crunch and Peer Encouragement
We'll set an official goal of having the post put up by midnight. Also, we'll meet up in a special-purpose discord channel to chat, encourage each other, swap half-finished drafts, etc. If like me you are intending to write the thing one day eventually, well, here's a reason to make that day this day.
2. Lower standards via Time Crunch and Safety in Numbers
Since we have to be done by midnight, we'll all be under time pressure and any errors or imperfections in the posts will be forgivable. Besides, they can always be fixed later via edits. Meanwhile, since a bunch of us will be posting on the same day, writing a sloppy post just means it won't be read much, since everyone will be talking about the handful of posts that turn out to be really good. If you are like me, these thoughts are comforting and encouraging.
Evidence this Works:
MIRI Summer Fellows Program had a Blog Post Day towards the end, and it was enormously successful. It worked for me, for example: It squeezed two good posts out of me. (OK, so one of them I finished up early the next morning, so I guess it technically doesn't count. But in spirit it does: It wouldn't have happened at all without Blog Post Day.) More importantly, MSFP keeps doing this every year, even though opportunity cost for them is much higher (probably) than the opportunity cost for you or me. I don't know what else you had planned for Saturday the 29th... (Actually, if you do have something else planned, but otherwise want to participate in Blog Post Day, let me know. Maybe we can pick a different day.)
It'll be fun!