Just the normal stuff.
Tube, CO2 inflater, two cartridges, patch kit, Topeak Alien II multi-tool (everything you could ever conceivably want, weighs a ton, but good for the boonies), tire levers, brake cable, derailleur cable, three links of chain, master link, Epi-Pen, emergency blanket, retractable cable lock.
That's it. Back-up mini-pump lives on my frame, everything else goes in the jersey pockets.