Woof
Select the Help menu
Select About Plug-ins
Select Acrobat Forms
Hold down Control
Press the Credits button
Listen to 'Woof' and see the paw of a dog appear.
The Credits button should say 'Woof' now.
You can repeat as long as you press Control and press on the Woof/Credits button.

Harpoon
Select the Help menu
Select About Plug-ins
Select Acrobat Annotations
Hold down Control
Press the Credits button
You'll hear a sound (probably a whale) and see the picture of a whale appear. The Credits button should say 'Harpoon' now.
You can repeat as long as you press Control and press on the Harpoon/Credits button.

3Self-Sign Signature
Select the Help menu
Select About Plug-ins
Select Acrobat Annotations
Hold down Control
Press the Credits button
The credits window will break open
The names of the people who worked on the project will pass by
They will Self-Sign the window with their signatures
They wish you good night!
The window will close again.
You can repeat by holding down Control and pressing the credits button.