Client/assets/js/eastereggs.js

// You're kind of ruining the surprise by reading this, but whatever
var today = new Date();

// Check Christmas season: Date constructor in Javascript uses an index
// so 11 is Dec. of this year, and 12 is Jan. of the next
var christmasBegin = new Date(today.getFullYear(), 11, 23);
var christmasEnd = new Date(today.getFullYear(), 12, 8);
var sf;

if (today >= christmasBegin && today <= christmasEnd) {
    console.log("Christmas Activated.");
    sf = new Snowflakes({ zIndex: -100 });
}

function stopEasterEggs() {
    if (sf != null) {
        sf.destroy();
    }
}