Need Some Ideas for a Hero Arena

For one I'm making this for my friends and my clan rather than the general public so don't worry about the whole '' Not another Hero Arena..." thing. I was just wondering what kind of features do you think Hero Arenas are lacking and what current features need to be tossed. Any ideas willl help.

make some traps that will either kill, damage, or send some really though encounters in the arena :D that would be cool, and dont have tomes in it... cause it just ruin it for the loosin yeam big time !

Miniature quests with fellow heros for items might be a good idea.

Maybe small armies spawning based on the hero's level and stats and fighting instead of the heros alone.

Oh and feel free to give some spell ideas too(most spells will be trigger based so go overboard).