To elaborate, the floorboards to cover the ice, the basketball court, and associated stuff (basketball hoops etc.) are stored underneath the South stands in a large room basically the entire length of the ice. The problem is that space for improvements is non-existent. The North side is filled with three, not very big, locker rooms (Vistor, Aces, UAA, plus a trainers room that UAA/Aces share) with a locker room/break room for employees there as well. The Northwest corner is the entrance plus a few small rooms, The West end is the offices. The Southwest corner has a small VIP room, the referees locker room, and some storage and mechanical rooms (plus an entrance that's used during concerts). The Southeast corner is an entrance and where the ice making system is. The East side is where the Zambonis and stuff are. The Northeast corner has the elevator.
Basically building a storage room opens up a huge amount of space for things. The biggest things I could see back there would be new locker rooms for UAA and the Aces.