Question: It is often said that Nibbana is unconditioned. But isn't Nibbana to be attained through practice of the Noble Eightfold Path (abandoning desire, meditation, realizing paticcasamuppada etc)? Aren't those practices conditions for Nibbana? What am I missing here :) ?

Answer: 
The practice of the eightfold noble path leads to the *experience* of nibbāna, just like the act of adverting the mind to the eye door leads to seeing light. Light, the object of seeing, is saṅkhata (conditioned), but nibbāna, the object of supermundane consciousness, is asaṅkhata (unconditioned). So nibbāna isn't the result of the eightfold noble path, the experience of it is.
In the material world alls phenomena arises and passes based on conditionality (as opposed to totally random). In Nibbana there is no arising and passing away of phenomena.

It is true that realising Nibbana is the result of practising the path to realise it, hence if you have realised Nibbana then this is because you practice the path.