PUTPBAD is a very short work of Interactive Fiction written by Spatch. Contrary to what the above writeups imply, it is actually a beatable game; picking up the phone booth (and dying immediately thereafter) is not the only option.
(I didn't even know this... I actually had to disassemble the game before I knew there was an answer to be found... Just call me stupid.)
Since it is a spoiler, I'll put it in ROT-13:
Xabpx bire gur rivy cubar obbgu! > CHFU CUBAR OBBGU