Zhukov wasn't particularly known for being a joker. Having read several biographies, his memoirs, and other works that touch on him, I've really encountered nothing that discusses Zhukov being the type to enjoy cracking wise. Not to say he couldn't tell a good joke. He makes note of one or two in his autobiography, but not are quite what I would call mischievous. In his own recollections, Eisenhower doesn't record any examples, since he is writing in hindsight, but wrote of their 1955 reunion:

He spoke as if he was repeating a lesson which had been drilled into him until he was letter perfect. He was devoid of animation, and he never smiled or joked, as he used to do. My old friend was carrying out the orders of his superiors. I obtained nothing from this private chat other than a feeling of sadness.

Which certainly implies a somewhat lighthearted demeanor when they worked together in Berlin a decade earlier, and in his personal correspondence with his wife he gives off a bit of the same, such as poking fun at how he looked in a nightshirt that she had sent him at the front.

So in short, no, Zhukov wasn't a joker. Not devoid of humor, certainly, but not the image he cultivated. Its hard to cite something that isn't, but this is based primarily on readings of "Stalin's General: The Life of Georgy Zhukov" by Geoffrey Roberts and "Marshal of Victory: The Autobiography of General Georgy Zhukov", edited by Roberts as well.