I'm no expert on LN2, but I got many chances to play with it in college. U of IL had a program called the Physics Van where college students went to local schools to teach students from grade school up to high school about physics. The demos with LN2 were always the biggest hit: using a frozen banana as a hammer, LN2 powered cannon, sealing a jug filled with LN2 and watching it explode, and the famous Soap Explosion - dumping a bucket of LN2 into a bucket of soapy water. Since the university made the stuff we could use as much as we wanted. It was really fun to take the extra LN2 to the top of the lecture hall, dump it down the stairs and watch it boil away.
Note: always know what you're doing, you can get hurt if you aren't careful.
Back to the topic at hand...
Gui: no problem digesting the ice cream. the LN2 would boil away quickly and you wouldn't consume any of it. Besides, there's nothing wrong with swallowing Nitrogen, you do it every day.
Rob: you're used to the flavor of Nitrogen, it's the most abundent element in the air you breathe. But the ice cream may taste like the machinery that was used to make it
Ian: make sure the ice cream is actually warm enough to eat before you dig in.
Mike