(Works on Palm OS v5 devices including (but not limited to) the Tungsten|T, Tungsten|T2, Tungsten|T3, Tungsten|C, Tungsten|E, Zire 71 and Garmin iQue 3600 handhelds.)
1) Go to Prefs / Power.
2) Draw a small circle in the bottom-right of screen, above the Calc silk-screened icon.
A small Easter Egg will appear.
3) Tap Home / Menu / Options / About Applications.
4) Press & hold the Page-Down hardware button while you tap on "OK".
5) Repeat the previous step 3 times. On the 3rd repeat, hold the Page-Down button down to view the Easter Egg.
What will happen? The screen will turn black, then flames will begin to rise with a message written in the flame. Enjoy!