Since no main characters ever actually go into the Ares Cabin in the books, there probably isn't a canon description of it. The only thing known about Ares Cabin is the outside:<br/><br/><div class="quoteheader"><div class="topslice_quote">Quote</div></div><blockquote class="bbc_standard_quote">Ares' cabin (#5) is (badly) painted a bright red with barbed wire on the roof and a stuffed boar's head on the doorway. The eyes of the boar seem to stare at whoever is walking by. Apparently, there are also landmines surrounding it. </blockquote><div class="quotefooter"><div class="botslice_quote"></div></div><br/>But I think it's safe to assume a military like inside. I tend to go with the Camp Half Blood Wiki (http://camphalfblood.wikia.com/wiki/Ares%27_cabin) rather than the Wikia. There isn't much different, but the Wiki tends to be more canon based. Feel free to make up what you think the inside of Ares Cabin looks like. ^^