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):
.--
.--
.-'
.-'G
/REE
./
/NC o
/HEES
|EGREE
/NCHEE Last Quarter +
| SEGR 4 5:15:33
|E ENC New Moon -
| 3 7:59:30
\ . H
|
\
\ o
`\
\
`-.
`-.
`--
`--