WordDuel
WordDuel, also known as MasterWord, is a word guessing game. This version supports 1 to 32 players, and boasts a crude CPU player.

Download WordDuel (OS X 10.4 and higher)

FoxCrypt
FoxCrypt is a powerful encryption program for producing keyword-encoded files or text. It also features a Cryptograph function, just for fun.

Download FoxCrypt (OS X 10.3 and higher)

Howler
Howler is an easy to use kitchen/laundry/coffee/whatever timer with several useful features:

-Fast input and start of timers without mouse interaction
-Create as many timers as you want
-Set a timer with an end date (alarm)
-Remembers your last set timer
-Allows you to play whatever sound file you want for the alarm
-Convert temperatures C <--> F

Download Howler From the Mac App Store