Dumpling-sized balls of ice-cream surrounded by sweetened, flavored mochi. You bite into one... first chewy sweet ecstasy followed by creamy cool ice-cream bliss. It's best to eat these when they're slightly thawed, or else it's like biting into a ball of concrete, and we all know that's no fun.

I've seen/eaten mochi ice-cream in these flavors:

Kona (aka Coffee)
Green tea (my personal favorite)
Red bean (Azuki beans. Actually tastes a bit like strawberry, oddly enough. A close runner-up to Green tea)
Strawberry (Kind of bland, actually)

They all have their own flair. I only get to partake of this ambrosia a few times a year when I ride the train to Little Tokyo, in L.A.. Look for them in the freezer case at your Japanese market.