I installed WP Captcha Free here the other day, but it appears to be a broken plugin at least with this version of WordPress. The trackback from Tommi's post about using random encounters in his fascinating dungeoncrawl game was never recognised, and Jonathan from The Core Mechanic emailed me to say that comments were being eaten by an "invalid data" error. Damn.
So, goodbye WP Captcha Free! You sucked, and I really should have done... um, any testing after installing you. Lesson learned.
I've got another post brewing about random encounters, inspired in part by some links that Jonathan's been collecting on Gygaxian naturalism.