The newly renamed "Isles of Battle" now has two arenas. The old one is still available as well as a new "Coliseum". You'll also find a tavern to meet up and issue challenges, complete with Vault access. When the new food/deathpoint system goes in, the tavern will also be a useful place to eat away the deathpoints earned in the arenas.
Feedback is appreciated (this being my little pet lunchtime project). Check it out!