Blow up your balloons to about 3-4" across. 5" balloons are harder to blow up, consider using some kind of air pump. Adding cooking spray can help when removing it from the chocolate, but is optional.
Melt your melting chocolate in a double boiler or heating bowl. Do not get it too hot or it will become too thick for dipping.
Dip the balloons halfway into the melt. If the chocolate seems thin, dip it a second time. Set gently on a tray lined with wax paper.
Don't leave your balloon in the chocolate for too long, or explosions will happen.
Once a tray is full, place it immediately in the refrigerator to help with the setting process. Allow them to cool for at least an hour, preferably overnight.
Once the shells have completely hardened, poke a hole in the balloon and slowly let the air out of the balloon. Gently pull the balloon out of the shell.
For the ganache, place the chocolate chips in a heat proof bowl. In a saucepan, gradually heat the heavy cream until it comes to a simmer.
Pour the cream over the chips and allow it to sit for 5 minutes. Then, slowly stir the mixture until it becomes a smooth ganache. Place it in the refrigerator for at least 30 minutes.
Remove the ganache from the fridge and with an egg beater/electric mixer, begin to whip the ganache. The ganache will become lighter in color and take on the consistency of mousse.
Using a spoon or pastry bag, fill your shells with the whipped ganache. Garnish as you like and serve chilled! Store in the freezer.
Visual ingredient list, for reference.