Ergh. Thanks for the heads-up, Jason; I’ll see if I can figure out what the deal is. (Anybody else having that issue?)
The CAPTCHAs, alas, are a built-in feature of ExpressionEngine, so I can’t recommend an easy plugin for MT to you, but I’m sure somebody’s built one. And I highly recommend implementing something like that — it’s possible that the CAPTCHAs have dissuaded some more casual folks from commenting, but they’ve cut my comment spam to almost nothing.
**frantic knocking on wood**