Video embedding: The vshare plugin allows you to easily embed video in a page. Click the clapboard icon on the editor toolbar and paste in the URL. The plugin can handle URLs from Youtube, Vimeo, Ustream and many other sites; see the vshare plugin page for details.
Hideable sections: By request of JRSPhoto, I've added the hidden plugin. This adds "click to show more" sections on a page. Click the custom button on the edit toolbar, then choose an option:
- Basic Hide Block makes a block with "Click to display ⇲"/"Click to hide ⇱" text.
- Custom Hide Block lets you customize the show/hide messages.
There are a few other options you can set, which are described on the plugin's page.
Lastly, if there's a Dokuwiki plugin that would help you do something cool, please let me know and I'll look into adding it in.