Well... Our spirit is self-developed.
We started with a few enthusiastic members that try to overpower the teams much larger than ourselves... The programming team in particular screamed '1785' or 'blue/red alliance' or just bestial screaming from the depths of our throats until or voices gave and our throats bled... literally.
We had to drink cough syrup after Denver a few years ago ^^ I have no regrets!
As far as everything else we have, we made it with items lying around the school that would have otherwise gone unused...
But I think that spirit equals enthusiasm, not just the flashy banners and displays.
After all, we must have made impressions with just our voices!