Bot Invasion! Help!

I’ve been having all kinds of trouble with getting PayPal to work right on my Social install. aecnu /Joe informed me that one problem with the Membership plugin is that it doesn’t like Bad Behavior (or vice versa, if it matters).

OK. That’s not good, because Bad Behavior is one of the plugins that keeps my new site from being overrun by bots! Bad Behavior was shut off earlier today and I’ve already had 7 – count ’em, 7 – fake signups. That’s more than the real signups today! If this the beginning of a trend line, it’s not a good one.

You can see what I mean:

So, what do I do?

If I can’t use Bad Behavior, are there any alternatives that get along with the Membership plugin?