I hava a calendar (with two different views) which is "upcoming" and "past events". "order" is by date ACS / DESC.
You want it different, changing just the tpl. Maybe you dont need to. Because: you have the TV which is nessesary to filter / select the upcoming / current events. So you can use that TV inside the tpl chunk like:
If the difference between today and date_of_document id >30d, then please write class="event old" instead of class="event current".
So you need the today snippet (which returns the current date) and an output modifier
from here.
Cheers!