The latest Events module, version 3.3.8, uses themes to design the way it looks. Each module instance can have it's own theme. You select a theme in the module settings, Event Module Settings section,  from the Theme/Skin drop down list. Try the FixedBlue theme - despite of it's name, it shows the month view in full width.

To create your own theme, go to the DesktopModules\Events\Themes directory of your DNN installation. For each theme there is a subdirectory, which name determines the theme name. Each subdir contains a .css file. Just copy an existing theme subdir, rename it and change the CSS definitions as you like. The next time you go to the module settings page, the new skin will be available in the Theme/Skin drop down list.

If you're using an older Events module version without themes (I'm not sure if Events 3.3.7 ´had themes already, version 3.2 definitely hadn't), go to the DesktopModules\Events\module.css file instead, look for the .Event style definition and change it's width properiy to 100%.

Hope that helps! Have fun with DotNetNuke!

Well, I've never seen THAT before... Did you use the FixedBue theme, or a theme you've created yourself? And what happens if you return to the Default theme? What other modules are on that page? What happens if you delete them?

However, the scrollbars belong to the FixedBlue theme. (Now I know why it's called FixedBlue: the cell sizes are fixed, not the calendar size!)