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
/@@@@
|@@@@@
/@@@@@ Last Quarter +
| @@@@ 3 19:40:11
|@ @@@ New Moon -
| 3 9:19:44
\ . @
|
\ @
\ o
`\
\
`-.
`-.
`--
`--