Comment Expirator allows to schedule closing of comments, trackbacks and pingbacks on an individual basis at a date or time of your choice. It can be activated on any post type that allows comments. This is good for preventing spam on old posts. The plugin lets you chose if trackbacks and pingbacks should also be closed at the same time.

Comment Expirator

Comment Expirator let's you close comments, pingbacks and trackbacks on your posts, pages and custom post types on an individual basis.

Eric Binnion

cranewest

Allows admins to deactivate a user as opposed to deleting a user. Works with web and XML-RPC based authentication.
Once installed and activated, a checkbox appears on the user profile settings page. When checked, the user will not be able to login with the account. If they attempt to login, <code>This user has been deactivated. Please contact the administrator.</code> will be displayed in the login error box.

Deactivate WordPress Users

Allows admins to deactivate a user as opposed to deleting a user. Works with web and XML-RPC based authentication.

Comment Expirator vs Deactivate WordPress Users