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 .
.-' . O .
.-'@ @@@@@@@ . @
/@@@ @@@@@@@@@@@ @@
./ o @@@@@@@@@@@ @@@
/@@ o @@@@@@@@@@@. @@
/@@@@ . @@@@@@@o @@@
|@@@@@ . @@@@
/@@@@@ O `.-./ . @@@ Full Moon +
| @@@@ --`-' o 5 23:21:31
|@ @@@ ` o . Last Quarter -
| @@ @ .-. 1 0:46:16
\ . @ @@@ `-'
| @@ @@@@@ .
\ @@@@ @\@@ / . O
\ o @@ \ \ /
`\ . .\.-.___ .
\ `-'
`-. o / | o
`-. / .
`--. .
`--------