I think there are some pop/push mechanics for working directory too, but I can't find them right now.
Oh handy! Hadn't come across that before. Thanks.
The commands are pushd and popd, and they're bash (and zsh, and most sane shell) builtins. Pushd to get to a new directory, popd to go back to the last one on the stack.
Tip : Setting cd as an alias for pushd make the whole thing much more intuitive.
Or type `cd ~username` to goto that user's home path