Sure, Valentines day (or as some like to call it, Singles Awareness Day) is a great day to hatch plots and schemes, but that doesn't mean it's the only time. Reflect on a time where you executed an elaborate plan for someone. How did they react, how did they feel, and would it be worth doing again?
Group scheme? Years ago I volunteered at a Girl Scout day camp near San Francisco and we had one over night sleep over during the week of camp. As everyone sat around the fire, the camp leader told a story of fairies who painted rocks with glitter, among the other stories and songs. Very late at nigh we crept between the rows of sleeping girls and put small white stones with glitter on them near the head of each girl. I'm sure some of the girls knew what we had done, or had woken up and saw us, but no one spoiled the magic and there were proper ooohs and ahhhs at the glittery fairy rocks =) I'm sure I still have my fairy rock somewhere around here...
Heck yeah it'd be worth doing again! Spread the fairy magic!