I never really grew out of thinking the dry ice in the punch bowl was cool...
Lots of other good food ideas that I can't improve upon.
We used to make Pangalactic Gargleblaster Punch
1 bottle soda water
1 can orange juice concentrate (and/or pineapple juice, adjust the amount of soda water)
few* ounces of peach schnapps
few* ounces of Blue Curacao
add ice and dry ice just before serving
* exact definition of few is up to you