A seasonal opportunity to show how easy it is to transpose a song into different musical modes.
I use 'Jingle Bells' and change it from being in the major key (Ionian mode) of B into B Dorian; B Phrygian; B Lydian; B Mixolydian; B Aeolian and unfortunately B Locrian (sorry) ;)
Jingle Bells is a simple I IV V song, so by simply counting 1-4 and 1-5, and reading off the chord, the song can be changed.
I then show how easy it is to play the melody using the same minor pentatonic / minor scale shape. Its an interesting feeling to find yourself playing naturally in each mode, creating that distinctive sound but playing within the same pattern!
Hopefully the fabled lightbulb will go on for you as you try this. :)