Another option in Office 365 (and Office 2013, I believe) is to create a PowerPoint, rehearse the timings and add narrations, then use File > Export and save it as a video. Here is a 54 second one with a little music and some animations. If you know some Greek, you may actually think it's a bit humorous!
Click here or on the graphic above: Ἔρχομαι and πίνω
I've also used programs like Camtasia for screen recordings. It's more work to use this, but the results are a bit more polished. In any case, see what you think, and let me know if you have other ways for producing videos like this. Thanks.