I tried - but it was loading very slowly.
R.e. the widget template - the widget template is just a placeholder, that allows you to use tags (such as
%start% etc). Documentation is a bit hidden away at the bottom of this page: http://www.harriswebsolutions.co.uk/event-organiser/documentation/shortcodes/event-list-shortcode/ - but that's nothing to do with what you're seeing.
Not sure where the word 'CONTENT' came from or where it went - but how the events page is now displayed is not that uncommon. Basically the default template files for these pages (in this particular example
single-event.php) don't work well with your theme - nothing major, but one-size never fits all.
To fix it you can copy the templates (in
event-organiser/templates) into your theme folder and edit them there. The
single-event.php probably wants to look like your
single.php - so you can use that as a base. You can the include event specific information by using the available functions (you want to display the category or a venue map etc).
By copying the templates into your theme your changes will survive a plug-in update. There's more information on this page.
Hope that helps!