After getting back from the holiday, I decided to upgrade our events module on staging and it appears the issue is back.  Unauthenticated users are freezing every second click of the month.  I reviewed my settings and we do not combine/minify the js/css in our host settings.  I did increment the version just to be on the safe side.  Like Karen, I noticed a javascript error, so I created a new page and plopped a new events module on it.  Same error appears.  Error below:

Uncaught TypeError: undefined is not a function jquery.js:9597(anonymous function) jquery.js:9597Telerik.Web.UI.RadWebControl.raiseEvent jquery.js:9597Telerik.Web.UI.RadCalendar.raise_load jquery.js:9597Telerik.Web.UI.RadCalendar._ Handler jquery.js:9597(anonymous function) jquery.js:9597(anonymous function) jquery.js:9597Sys._Application.raiseLoad jquery.js:9597Sys._Application.initialize jquery.js:9597b jquery.js:9597document.addEventListener.a jquery.js:9597

Still working on it. It is not a simple fix, it is an incompatibility between the latest DNN cleanup, MS Ajax, Telerik and the rather old  calendar control used by the Events module.

it will be solved, but it takes work.