Okay, I am locking this topic for two reasons:
1: Liquid nitrogen is not safe to be handled by non-professionals - so I am locking this to prevent people from replying with "If you do X/Y you can do it safely" posts.
2: Liquid nitrogen is damn dangerous and should only be handled by professionals - yes, I realise I said the same thing two different ways... that is just to emphasise.
Dry ice is in fact quite a dangerous compound, but with careful handling, we use it in the theatre to great effect. Liquid N2 is many times more dangerous - especially in the quantities required for stage, and in most countries (The US, I am not so sure about) requires a permit to get such quantities - and there are a lot of storage considerations to be thought about - making using liquid N2 prohibitively expensive.
If the OP wants more information on using liquid N2, then the OP should contact a local effects professional and proceed from there.