Hi,
A summary of the two new hopefully interesting features related to custom widgets for you (available in the next snapshots):
Import custom widgets from GitHub
I want to encourage the distribution of widgets from GitHub repositories (like @pmpkk did, a very good idea) instead of attaching them here, for several reasons:
- Versioning and updates are far easier;
- No need to have an account and login to download - a link to the repo is enough;
- Ability to import - or update! - several widgets at once.
The only requirement is to put your *.widget.json files in the root folder of the repo, as the import feature dosen’t look recursively inside directories.
Opening threads here and discussing your widgets is of course still appreciated, but you may provide a link to your GitHub repository instead of maintaining file attachments inside your posts 
Updating the widgets (individually or at once) or opening their Readme from the list are now a breeze! But unfortunately there is no solution yet for importing static files from the repository, so you’ll have to describe those manual steps in your Readme…
Eventually this feature will be expanded to include more sources for widgets, with a gallery maybe.
Beware, the GitHub API has pretty harsh rate limits so if you hit this feature too hard you might receive an error telling you to wait a little! (60 requests per hour IIRC)
Custom widgets as main menu tiles
There is a new (experimental) option to replace a main menu tile by a custom widget - a configure it like a normal one. This means dynamic content is now possible in the main menu! Avoiding interactivity in those widgets is advised though, because clicking them will still take you to the associated dashboard (though you can stop event propagation - with $event.stopPropagation(), google it).
Enjoy!