This comes from Club Revit's Linked In page. A user asked how to change the number of lines in a room tag and Kerry Ward had an interesting take on things. She provided this trick...
"Name the room (single line text) then select the room (not the tag). Go to properties and under Identity Date / Name place your cursor in location where you want the text to split into 2nd line. Then hold down ctrl key and press enter, then apply. The room tag is then split into 2 lines."
I added quite a few breaks in the example image below to demonstrate how far you can take it. You can see that it comes with the side effect of reflecting in schedules. On the MEP side of things it may not matter at all.
If you are curious, changes the room names in linked files will propagate into the space tags that call the room names.