After submitting a bug report I was led to the solution.
Under "Manage Groups" take a look and see if you have any Members listed in the "Guest" group.
Click the Members link in the Options column.
You should have "Anonymous" as a member of this group.
If Anonymous is not listed go to "Manage Users"
Check the "Select Anonymous User" box and click Submit
On the far right you will see "Select Form"
Pulldown and choose "Groups", click Go
If Anonymous is not already in the Guest group you will need to add them
On the bottom right you will find "Add User to Group", select Guests, click Submit
Confirm that Anonymous has been added to the group guests.
If you have already set up your Permissions you are done and your forums should be viewable.
If not, do the following:
Go to "Groups' forum permissions"
Next to "Look up usergroup" select Guests from the pulldown, click Submit.
Select "All Forums" (or the ones you'd like to make viewable to Guests), click Submit
Confirm that all the permissions are set to "Read Only"
I could have sworn I was able to see the forums without logging in. Then suddenly I could not.
Maybe it's a bug, maybe it's me not being able to remember correctly.
Anyone know the out-of-the-box default setting?
Oh well, it works.
Thanks for everyone's suggestions.