This one is from the amazing Rick Boatright. I saw the ancestor of this thirty-plus years ago in Unix System V, had no idea it had gotten so useful in Microsoft-land. The gist of it is:

• You have a batch file, and want to access something involving a UNC path, something like this: \\SERVER_NAME\share_name\dir1\dir2
• Default logic often involves storage of current location into a variable, CD, resumption of previous, blah, blah, blah.
• But we can do it in one command: pushd \\SERVER_NAME\share_name\dir1\dir2 This does multiple things:
• First, it creates a temporary drive letter for the server and share name. It chooses an available drive letter.
• Secondly, without any further ado, it changes the current working directory of the shell (of the script) to the very location you pointed at.
• So, if you did the pushd above, and if Z: were available, your current working directory suddenly becomes: Z:\dir1\dir2
  where Z: is mapped to \\SERVER_NAME\share_name !!!
• Then when you’re done with it, just put in popd, and Z: goes away and you’re back to the current working directory you had beforehand!