Easter Eggs
From Apache OpenOffice Wiki
Writer
StarWriter Team
Enter the word "StarWriterTeam" into a Writer document, then press F3. The picture of the StarWriter Team appears.
Calc
Tic-Tac-Toe
Put the =GAME(A2:C4;"TicTacToe") formula into A1 and press ENTER. A version of the Tic-Tac-Toe game is playable.
Space Invaders
Put =GAME("StarWars") into any cell and press ENTER. A version of Space Invaders is playable. Although if you try to play it again, the message "oh no, not again" appears. To play again, you must fully close OpenOffice.org.
Life, Universe and Everything
Put =ANTWORT("Das Leben, das Universum und der ganze Rest") into any cell and press ENTER. The result is the famous number 42 from the Hitchhiker's Guide to the Galaxy.
StarCalc team
Put =STARCALCTEAM() into any cell and press ENTER. The picture of the StarCalc Team appears.