If you visit the Kanbar Performing Arts Center any afternoon of the week, you'll hear lovely singing all around. It's entirely possible that amongst that singing will be the simple, catchy, and enduring "Jee Jaw Jee" warmup below. I don't know why I like this one so much, or why it seems to be a favorite of my colleagues and students, but perhaps it's due to the bouncy rhythm, or the buoyant, effervescent feeling you get when you do it right. In these few sentences, I've already built it up to be more than it is in actual substance, but give it a try and see what you think.
Similarly catchy, but slightly more difficult is "Kee Yaw Kyaw." This one hails from the late, great Barbara Kierig (and, she would've told you, from Tovini before her. "He was an utter god, Honey!"). Her original was slightly different, putting the 'kyaw' on the top note of the exercise. When we worked on this one, I usually lost my grounding and ended up choking on my larynx, so she moved the 'kyaw' one note earlier so I could slide up to the top and try to maintain a neutral, relaxed laryngeal position. It's a small example of flexibility and pragmatism that was a hallmark of our work together, and that I try to practice with my own students. After all, as Barbara said time and again, "You have to do what you have to do to get it to do." So there.