You can do one spontaneously from this post! (Covid might impact results of course) I met with a group a couple of years ago that just said "who wants to meet at 1pm today at Jason's Deli?" About a dozen people showed up!
The best RE meet-up in Houston I've found is "H.I.T. (Houston Investment Team). It's hosted by BP member and KW agent, Matthew Gullo .
The meet-up has been virtual since COVID. I'm not sure if there is a timeline as of yet for when it will transition back to it's standard format - it was previously hosted downtown in the Galleria.
Shoot Matthew an add and I'm sure he'll get you the details. Hope this is helpful!