Even though the sound quality is never really that good, I find internal speakers very handy for times when you can’t be bothered connecting up real speakers.
The Mac mini which is donating parts to this project had a speaker so I am experimenting with a tiny low voltage amplifier to drive it.

Here is one built around an LM386N. It’s driven by 5V and I am happy with the volume and quality for what it is.
The small circuit on the left is for getting 5V out of the 18.5V power brick.