Responding with humor to the question "What's up?" can add a light-hearted and entertaining touch to your conversation. Here are some funny responses you can consider:
"The sky! But if I jump, maybe I can touch it."
"Oh, you know, just pretending to be an adult. It's not going too well."
"Not my cholesterol levels, that's for sure."
"Just trying to avoid responsibilities like a pro."
"My mood ring says I'm either a unicorn or a potato. Not sure which one yet."
"Up? Oh, I live in a bungalow. Nothing's up."
"I'm like a ninja—always lurking in the shadows."
"I'm on a quest to find the lost remote. It's a serious mission."
"I'm doing the worm, but vertically. It's called the 'caterpillar.'"
"The usual - attempting to adult, failing spectacularly."
Remember, humor is subjective, so consider your audience and their sense of humor before using these responses. The goal is to bring a smile to their face and create a fun and enjoyable interaction.