The term "ho hum" is often used to describe something that is dull or uninteresting. If you're looking for a way to express the opposite of ho hum, you might consider words like thrilling, exciting, exhilarating, captivating, or engaging. These antonyms indicate that an activity, event or experience is full of energy, or that it grabs your attention and keeps you intensely interested. Alternatives may include vibrant, stimulating, invigorating, enthralling, fascinating or electrifying. So while "ho hum" might describe something that's uninspiring or mundane, there are plenty of exciting antonyms to describe experiences that are anything but dull.