How to remove "/$MyDir"
For what it's worth, I have the same $MyDir folder at the root level of my HD. When I did a date restricted search, I found that the folder was created in the middle of installing Google Sketchup 6. Can't say why or for what reason.
I too have this directory. Based on your info, mine also appears to be associated with the installation of Google Sketchup too (which I have since removed). I hadn't made the connection until I read your message, but date stamps on my backups prove what you mentioned...
FWIW: I'm running Tiger (10.4.11) and haven't done anything with Leopard (on this drive).
Here's some interesting terminal output....
cd /
SRP-MBP:/ sparker$ ls -al
drwxr-xr-x 2 root admin 68 Jun 17 2007 $MyDir
<<<<<SNIP>>>>>
SRP-MBP:/ sparker$ cd $MyDir
SRP-MBP:~ sparker$ pwd
SRP-MBP:~ sparker$ cd /
SRP-MBP:/ sparker$ cd "\$MyDir"
SRP-MBP:/$MyDir sparker$ pwd
/$MyDir
SRP-MBP:/$MyDir sparker$ cd /
SRP-MBP:/ sparker$
Since there is no variable $MyDir, the "cd $MyDir" command by itself resolves to "cd " which, by convention, changes to your Home directory.
To remove this directory, open terminal and type the following (which will require root password)
WARNING: WARNING: WARNING:
DISCLAIMER: If you mistype the following command, you'll end up removing your entire home directory!!!!! BE CAREFUL, and be sure to get the back-slash in the right place (after the first quote, and in front of the "$") I'd strongly suggest backups before doing this, and if it breaks, don't blame me!
cd /
sudo rm -rf "\$MyDir"
<<<you'll be asked for your admin password here>>>
Steve