First, the baseline info: https://en.wikipedia.org/wiki/Xbox_Underground
Now, the new WIRED story:
For fees that ranged up to $100 per half-hour, players with JTAGed consoles could participate in death matches while wielding superpowers: They could fly, walk through walls, sprint with Flash-like speed, or shoot bullets that never missed their targets.
For an extra $50 to $150, Pokora and Clark also offered “infections”—powers that players’ characters would retain when they joined nonhacked games. Pokora was initially reluctant to sell infections: He knew his turbocharged clients would slaughter their hapless opponents, a situation that struck him as contrary to the spirit of gaming. But then the money started rolling in—as much as $8,000 on busy days. There were so many customers that he and Clark had to hire employees to deal with the madness.