Moe said:
Now, is there something these days, like
SoundMaster, that allows you to tie them to certain system events?
I don't know of a nice neat way to do it, but there is a messy way.
Many are hiding inside /System/Library/Components in CoreAudio.component. You may want to save a copy of this before playing, since going inside is kind if the modern equivalent of mucking with ResEdit.
Ctrl-click and show package contents, then go down to Contents/Resources/SystemSounds/ . Inside those folders are most of the interesting noises. You can replace the sound files. I don't know of any extension that would swap them temporarily without doing that.