Author: Jorge Abel Ayala Marentes

Many world class applications implement some easter egg to give its author(s) 
credit, so why not to use this feature in your own applications?

Answer:

An easter egg is some piece of code that executes only when the user uses some 
special keystrokes, they are used frequently to give credit to the author(s) of 
some program. 

For example in Delphi´s About box hold Shift + Alt and then type "team", you will 
expose an easter egg giving credit to Delphi Staff. 

To create your own easter egg take this steps: 

1.- Start a new Project 

2.- Create the following private fields: 

1   private
2   FEgg: string;
3   FCount: Integer;


FCount holds a count of Keystrokes. 
FEgg holds the Keystrokes string. 

3.- Create two constants 

4   const
5     EE_CONTROL: TShiftState = [ssCtrl, ssAlt];
6     EASTER_EGG = 'SECRET';


EE_CONTROL contains the control keys that must be down when the user types the 
EASTER_EGG string 

4.- In the OnCreate event of the form write 

7   procedure TForm1.FormCreate(Sender: TObject);
8   begin
9     FCount := 1;
10    FEgg := EASTER_EGG;
11  end;


5.- In the OnKeyDown event of the form write 
12  
13  procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
14    Shift: TShiftState);
15  begin
16    //Are the correct control keys down?
17    if Shift = EE_CONTROL then
18    begin
19      //was the proper key pressed?
20      if Key = Ord(FEgg[FCount]) then
21      begin
22        //was this the last keystroke in the sequence?
23        if FCount = Length(FEgg) then
24        begin
25          //Code of the easter egg
26          ShowMessage('Add your own code here!');
27          //failure - reset the count
28          FCount := 1; {}
29        end
30        else
31        begin
32          //success - increment the count
33          Inc(FCount);
34        end;
35      end
36      else
37      begin
38        //failure - reset the count
39        FCount := 1;
40      end;
41    end;
42  end;


6.- Finally set the Form´s KeyPreview property to true. 

Now you just have to replace the ShowMessage with Something more creative, use your imagination!