1. vocal improvisation over a drum beat student has picked.
2. creating chords/harmonies with vocals through overdub recording with recorded audio vocals. for instance, recording do mi sol on one track, and la do mi on another, and switching between them.
3. composing a 30 second song cycle.
this article has good intentions, but it's a bit empty. It's more brainstorming rather than actual applications that may help you set up and practice a keyboard lab. Very general ideas.
how to use the acapella app tutorial video