Yeah, sorry about that Crash!
The file that stores the chatroom user information resides on a remote server, and the forum accesses it once every three minutes to update the stats at the top and bottom of the forum.
From time to time, the server that hosts that file stops responding. When this happens, the forum index script execution time increases dramatically to 45 seconds, and it makes the forum seem very unresponsive to members and guests.
When Jaime or I notice this is happening, we check the status of the remote server. If it is down, we deactivate the feature that lists the chat information.
I've got a complete rewrite of this feature on my list for our next upgrade (~6 months away, but don't hold me to that estimate).
It is back up now, and should be working fine.

Mike