Clever Method for Spam Protection

I'm sure many of you out there are like me and don't like dealing with a "recaptcha". I've seen spammers get through them with crazy spam invasions. To counter this I used a more sophisticated method via a "passphrase". Basically the admin can have it ask a simple question and the user can give a one word response. For example the name of my site is Alpine Ascent, I was able to ask "What's the first Word of the Site Name?". For years this method was very effective, users signed in with ease, and spammers didn't get through. The plugin was for Community Builder and has long since been abandoned (I might have the archive files of the CB plugin if that helps).

The only spammers that could get through are the human ones which are much fewer, a passionate admin could ward them off by blocking their IP and such. In addition to this, having a pass phrase could allow only specific people who know a secret code to join your site which could benefit clubs and niches. If we wanted to get really fancy we could allow multiple pass phrases that randomly generate so that passionate spammers would have to think the second time they come back.

This idea isn't just for protection, but is for our site users. We want them to be able to easily join. I have lost track of the dozens upon dozens of times I was annoyed with using a recaptcha from a user end. Dealing with a pass phrase, especially if the admin makes the answer super easy, is the way to go.