Had a particularly interesting experience this morning with the barely-restrained hostility between the mages at the AU and the Imperial Battlemages.
I was traveling with Clive the Imperial, and he stopped by the AU before setting out for Bruma. His last stop was the Praxographical Center, and when he left, he came face-to-face with Audens Avidius.
I thought, "Ooh... this should be good."
And it was - four or five of the mages surrounded him and just blasted him with an assortment of spells, It was about the fastest I've ever seen Audens go down. But then, just because I've seen this sort of thing happen before, I just waited. Sure enough, I heard a commotion up on the upper level near the entrance, and when I went up there, there was a full scale war going between the mages and the Imperial Battlemages. Luckily, I'd saved before making spells, so I just reloaded that save, made the spells over again (and hurried a bit) then rushed out and got through the gate and over near the entrance, where there was just one lone Battlemage at that point. And sure enough, within seconds, Audens came through the door and the Battlemage took him down. Then, without even pausing, the Battlemage started attacking Clive. Then, behind us, I could hear the mages coming through the gate and the war starting up again.
I finally ended up just reloading the save and leaving immediately, so Clive could wait by himself on the bridge to the Arboretum, where he dispatched Audens handily. I half expected the Battlemage to attack Clive anyway when he want back in to finish up his spellmaking, but he just launched into that "Ah... you must be the Arcane University's newest associate" routine. Bastard. I should've let the mages kill him.
I'm sure others have some good stories of that war that bubbles just below the surface at the AU...