NPR Training has some great vocal warmups:

If you pant like a Labrador will your voice have more energy? Can you hum away “vocal fry?” And what does Bugs Bunny have to do with good radio?

I coach reporters at NPR on vocal delivery — and these are some of the tricks we use. To really build a strong vocal presence for audio storytelling, I suggest you create a simple, daily warm-up routine that involves body, breath and voice. (And yes, panting like a dog is part of it).

Check out the link for all the warm-ups and the video connected on the “Three Tips for Training Your Voice”