I was getting ready for this years OSgrid 14th Birthday exhibit and pulled out some things I had made last year. I found these balloons I made that spell out happy birthday and play the birthday song while giving out a few fireworks. I thought, hey, that's festive and you never know when you're going to need birthday decorations (well, I suppose you do given the annual occurrence of birthdays :D).
They are out in the shop building and ready to party. Touch them for the song and display.