Since I've originally written this post, at least two calendar plugins have been updated to use custom post types.
Calendar Press looks like a really good option. There's also Kino Calender Plugin. If you're just looking for a plug and go solution, I'd recommend trying out on of those.
Thanks for the Kino calendar plugin, I've been looking for a good yet simple calendar for a while. Kino could use some more features, but works well and has multi-day visual support in the calendar widget.
This plugin adds an extra required field in the comment form. This is actually a checkbox with a link to your comment policy page. The visitor must accept the provided comment policy in order to submit a comment.