Phoon displays the phase of the moon, either currently or at a specified date / time. Unlike other such programs, which just tell you how long since first quarter or something like that, phoon shows you the phase with a cute little picture. You can vary the size of the picture with the -l flag, but only some sizes have pictures defined - other sizes use @'s.
Sample output (HTMLized via texttohtml):
--. `--. . `-. `-. . \ . \. \ @@@ \ o @@@@| @@ \ New Moon + @@@ | 3 4:04:52 @@@@@ | First Quarter - @@@@@ | 3 10:45:57 @@@ o / | o . / / .-. /' `-' / .-' .-' .--' --'