His hare-brained scheme to build a rocket out of cardboard boxes failed miserably.
Her hare-brained idea to quit her job and become a professional juggler was met with skepticism.
Their hare-brained plan to travel around the world with no money quickly fell apart.
Despite their hare-brained adventures, they always managed to have a good time.
Her hare-brained scheme to start a business selling homemade pet clothes was definitely a wild idea.