Look at these hoolahoops. You think you can put a generator in it and charge your phone or something?

https://cdn.fosstodon.org/media_attachments/files/111/183/898/035/639/082/original/628363841680932c.png

https://cdn.fosstodon.org/media_attachments/files/111/183/898/281/676/711/original/554e81ecd3020300.png