It really depends on how high up you are. If you're really low down, probably just scraping out sustainence and trying to survive. If you're really high up, doing whatever you want in between making sure you don't get killed by the people who want to be in your position, and of course trying to take the place of people above you.
I imagine a lot of them have jobs of various kinds, merchants are probably pretty common, selling off things stolen in realspace raids and from others in the city. If you have a few slaves you aren't going to have to do as much work, and if you're pretty high up and have a lot of slaves your 'job' would probably be managing them to get the most out of them.
Also don't forget the arenas which they can go to for free sustainance (assuming they're let in).
In other words, lots of things, only more dangerous.
"Oh how awful, did he at least die painlessly? To shreds you say? Well, how's his Dracon holding up? To shreds you say? Very well then... Sad, sad, terrible gruesome news about my colleague Archon Mhu'bhutu." - 'The Feather', Dracon of the Bladed Lotus