I found a way to stretch the box itself using CSS but not change the text. However, I am told by a nearby dev that it's possible. If I manage to do it, I'll post code here.

For now, here is the CSS that manually stretches the box. (It's not dynamic and can only used a fixed px height. If someone else can make it work dynamically and wrap the text, that would be AWESOME.)

/* this one is the container on all calendar views */

.fc-view-container * {

    min-height: 60px !important;

    overflow-y: visible !important;

}

There are also these two which do something, but I can't get it figured out:

/* this one is just month view event box */
.fc-day-grid-event * {
    min-height: auto !important;
    text-wrap: wrap !important;
}

/* this one does something */
.o_event_title {
    /*overflow-wrap: break-word;*/
    /*text-wrap: wrap;*/
    /*border-radius: 5px;*/
    /*padding: 2px;*/
    /*line-height: 10px;*/

    /*height: auto !important;*/
    /*min-width: 600px !important;*/
    /*min-height: 100px !important;*/
    /*overflow-x: visible !important;*/
    /*overflow-y: visible !important;*/
    /*height: 400px !important;*/
}

AND HERE is how I got the text to change. I found it in the base code and it's even commented to show you what to do... like the Odooers knew someone would want to do it.