OS X has a somewhat non-standard VNC implementation in ARD, and I have problems with it locking up, and not letting me back in. Thankfully, this service can be restarted remotely if you can still SSH into the system.

The ARD service is controlled by launchd, and will restart automatically if killed. To relaunch the service, simply run the following command (you must be an admin, or root):

killall ARDAgent

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