Vera Keyes' "Let the Bright Tomorrow in" song

 is a miscellaneous item in the Fallout: New Vegas add-on Dead Money. Rather than a cassette like most holodiscs, it can be found by accessing the music controls on the terminal, found on the desk by the front doors in the lobby of the Sierra Madrid hotel. Downloading the ambient music for the restaurant, executive suites and theatre will add a note to your Pip-Boy.

Activating the Greeter hologram from the same terminal will play some ghostly, almost indiscernable music, presumably featuring Vera Keyes' voice.