Simkhaster i gopen'ki

Recently, my memory spewed out a Yiddish expression my grandmother used to use to indicate messy situations people got themselves into or general madness involving several people. "So then David married Sarah and all of their children were at the wedding and her father got drunk and had to be carried home. In one word, simkhaster i gopen'ki," she'd summarize the situation with a sly smile.

I searched online to try to come up with an etymology of this expression, the mysterious "simkhaster" and the more understandable "gopen'ki" -- probably from the word "gop" or "hop" for jumping and running around. There were no hits on either Google or Yandex. So then I tried a different route and asked my dad if he had any idea what it meant. His explanation turned out to be surprisingly simple and illuminating. He says it comes from the holiday of Simchat Torah and the traditional dancing that happens during the festivities.