((Fair warning, I am quite new to forum RP. If I miss some part of the etiquette, you have my apologies.))
The Institute of War is a massive building, made out of stone bricks, like most constructions of this size, though it was no doubt created with the help of magic. Inside, each champion might find a room suitable for use as a temporary resting place, filled with some small creature comforts meant to soothe the minds of the champions when their summoning schedules get to be too hectic.
However, if one were to take a different turn, away from both the long hallway stretching far off into the distance, lined with rooms large and small, and away from the tunnel leading down into the summoning platforms where champions are taken to whichever battleground they have been called to fight upon, you might hear a very distinct sort of music.
Wandering down this offshoot hallway, most people notice it gets...darker, somehow. Some of the windows have been covered. Some fully, and some only partially, the latter windows allowing light through to dance on the floor in patterns that could not be coincidental. The two great wooden doors stand wide open, allowing access to the room at all times of day. Inside, there is a large stage, with instruments set up and ready to play.
This is the Institutes Grand Ballroom, open to all sorts of events and concerts.
((The only thing I ask is that if your characters leave the Ballroom, please don't continue their actions here, as it might clutter everything up, as well as make RP incredibly confusing.))