what the heck is a lak
It's a PoW-coin, based on Nxt AM. This coin is protected against 51% attacks by Nxt PoS algo.
Btw.
You mentioned that PoS is not going to stay with Nxt forever.
What is coming after the Proof of Stake?
Proof of bandwidth?
And "Proof of processing-power which is actually used to secure the network, not to brute-force some stupid hashes"
This would be kinda elegant.
Actually the Proof of X list is just as great as your imagination. (And probably technical possibilities at this point in time
)