Thank you to Dansmath for turning me on the website xtranormal. It allows you to create your own animated videos. It is easy and fun. You can choose the characters, the scene, the camera angles, the gestures and facial expression, music, etc. They do the voices for you—you just type the script. Here are some of Dan’s videos. Xtranormal is in beta and is free to use (for now, at least).
Here’s my first creation (watch out Martin Scorsese):
David Richeson: Division by Zero 
Fun. The text-to-speech function does not do well with formulae, it seems. Is there any way to insert pauses, e.g. “If x [pause] …” That would make it clearer.
Cool, yo! I think I would use this for class announcements… or for deadpan math jokes. Following math verbally is a bit nightmarish, unless there is accompanying text, methinks.
I agree with both of you. I had to write out the math phonetically (it took me a while to find out how to get him to say the letter “a”).
“…the limit as ex approaches eh of eff of ex…”
You can do pauses. I didn’t spend too much time fully exploring the options. Maybe a different (slower speaking) voice might be better too.