Random Bookmark is an extension that provides a toolbarbutton to open a random bookmark (from your Bookmarks Menu Folder, your Toolbar Folder and your Unfiled Bookmarks Folder) or history entry.
If random is too random, it provides the possibility to limit the randomness by defining filters, be it just with an url (e.g. youtube .com/watch) or with a regular expression (e.g. vimeo .com/[0-9]+).
It's also possible to select the bookmark source: Bookmark Toolbar, Bookmark Menu, Unfiled Bookmarks, or All Bookmarks.
Clicking the button will open an url in the current tab, middle click will open a new tab, and right click will open the settings menu.
"Random bookmark helps you to explore your browsers history, to select one of your favourite YouTube videos, or just to entertain yourself."