I thought that since Codechef is such awesome community, we can all vote here for the most interesting problems of 2016.
This list can be really useful for anyone who wants to improve his skill, or just have fun solving great challenges we had in 2016 and there were many of them!
RULES

Each person can vote for at most 3 problems which appeared in any CookOff, Lunchtime or Long Contest in 2016.

In order to vote, write your answer listing problems you vote for, and explain why there are interesting for you if you want.

After that, update total score of problems you are voting for in the below list, so if a problem is not on the list yet, then just add it with score 1, otherwise increment its score by 1. The topic is marked as “community wiki” so anyone should be able to edit it. However, If you are not able to edit the main post, just write a comment below and I’ll try to do it for you.

Whenever you link to a problem, paste the link to its contest version, not practice.
BEST PROBLEMS OF 2016
ASTRD : 2
KIRLAB : 2
BASE : 2
AMAEXPER : 1
BGQRS : 1
BOUNCE : 1
CHEFPOL : 1
CHNBGMT : 1
FLYMODE : 1
FRIEMEET : 1
KIRMEME : 1
LCPMAX : 1
LTM40EF : 1
MGCHGEOM : 1
POLYEVAL : 1
QUEHEA : 1
RESTPERM : 1
SEASTONE : 1
SHAIKHGN : 1
TULIPS : 1