Hi Luke,
At the present time, while we don’t have a dedicated responsive view, the calendar does look pretty good on mobile devices in a Twenty Twelve theme install. Well, except for the calendar/grid view.
A fellow user did come up with a reasonably easy work around that improved the responsiveness for them over here https://theeventscalendar.com/support/forums/topic/responsive-calendar-3/ and the specific code can be found here https://theeventscalendar.com/support/forums/topic/responsive-calendar-3/#post-60242. There was also a recent discussion of another approach over here https://theeventscalendar.com/support/forums/topic/responsive-calendar-2/ that some people found success with.
We’re actually working on a dedicated responsive layout at the moment for release sometime in the near future. However, we don’t have a specific timetable for it. In the meantime, I hope these customizations do the trick for you.
— Julie