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.

WWW: http://www.acme.com/software/phoon/