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.
When it says that "Anicca vata sankhara" ( Impermanent are all conditioned things). "Uppadavaya dhammino" ( Of the nature to rise and fall).
It is saying that things arise dependent on conditions, things "exist" because of the conditions that support them. So we are talking about characteristic nature of things or its attribute.
The attributes of nibbana as pointed out above is permanent, does not arise depending on conditions.