aha moment
A moment or instance at which a sudden, revelatory idea, realization, or solution to a problem comes to mind. We'd been working on the problem at the lab for weeks, but the aha moment came to me when I was out gardening!
do not spoil the ship for a ha'porth of tar
Do not ruin something for an avoidable reason. "Ship" is thought to be a dialectical pronunciation of "sheep," and a "ha'porth" is a "halfpennyworth." Tar was used to protect sheep skin from flies (and thereby illness and death), so not having enough tar would contribute to the death of the sheep. You know your mom is going to be offended, so please call her before the dinner party—do not spoil the ship for a ha'porth of tar.
funny-peculiar or funny ha-ha
A phrase used when the speaker is trying to determine if someone else used the word "funny" to mean "strange" or "humorous." A: "That play sure is funny." B: "Do you mean funny-peculiar or funny ha-ha?"