No Kids Allowed
Yes, it's OK to have a school event with no kids. In fact, I highly recommend it.
I think of PTOs and PTAs as communities of parents that help create the entire atmosphere around a school. Parent connections grow involvement and are also invaluable during tough times, so it's entirely appropriate for your group to hold events that foster those adult relationships.
It might be a restaurant night (have you seen our new sister site, Restaurant-Fundraisers.com?) or an annual dinner-dance at the Elks club or anything else. The group at my kids' school hosts a "college party" at a local place with karaoke and more shenanigans. It's a lot of fun, and school friendships (for adults) are made and extended. And that's the point.
What kind of adult tradition can you build? We have some great resources for this type of event, including flyers for moms night out, dads night out, and parents night out. And we'd love to hear what you've come up with on our Facebook page. Above all else -- have fun!