Engagement party idea: photos hanging from balloons to create a chandelier over a table... Love the idea of using this to create a cheap, but elaborate looking centerpiece over tables. Pictures could include the lovely "proposal moment" ones that Kelly sent us all the other day. I'm sure wedding guests would love to see them, too!
"Fire" & ice lantern - pretty awesome! Fill a balloon with water and let it freeze just enough for a thick shell of ice to form. Poor remaining water out, cut off balloon, and stick an led candle light underneath. This could be great for a party.