Processing shortcodes in descriptions is disabled by default; you can enable it in the My Calendar settings. Look for “Process WordPress shortcodes in descriptions” on the settings page.
Now, a word of warning – processing shortcodes can have some consequences. Depending on what plug-ins and theme you have installed, this can do anything from 1) fail to work, 2) break your site, or 3) massively increase memory usage on your site.
#2 is relatively uncommon, and is frequently caused by #3, but the main reason for this is the sheer number of processes that might be run – if you have a lot of events (say, 100 events in a month), you’re using the details pop-up (as opposed to opening in a new window), then every single function that’s supposed to run on post content will run over 100 times on a page load.
Additionally, shortcodes that depends on being inside the loop may not work correctly.
Whether this would be a problem depends enormously on how your site is set up, so it’s impossible for me to know for sure what will happen.
