Actually Rut does have a "n" in his word..."Chrunck"...maybe he changed it after this discussion.
Anyway, I am from the Pacific Northwest and have never heard this term used around here.
However, I did hear a NFL player on ESPN radio the other night use this term. Dan Patrick stopped him in mid-sentence and said, "What in the heck is Chunk?" He explained to him basically the same thing that Rut said...get excited, get hyped, etc.
Patrick kept trying to use it in his sentences...it was hilarious...he said he was going to use it in his next ESPN TV show.
RD