A bit too culture-bound for me to have got without an explanation.
Funny you mentioned that. I didn't get it either at first. It came to me what I tried looking up 'a pollster' under the U section of my dictionary. I thought, "What am I doing in the U's? And why am I looking up an article (i.e., "a"). It finally came to me, homonyms: a pollster/upholster. Haha. Tricky one indeed. 8)