I've got a story I think is pretty good. One time long, long ago (1st Edition), the team of razorguys, street mage, a decker and a rigger were up to their necks in dreck thrown at them from one mega-corp after another. Not enough to kill them, but enough to have them running scared, low on ammo, and a bit banged up. Wondering why all their chips were being cashed in, the runners discovered through a little jaunt through the Matrix that their group was suspected of possessing some primo loot that the corps just had to have. They also discovered that the burn order came down shortly after a little unsolicited visit to the mainframe of Ares Macrotechnology. After a bit of soul-searching, they finally stripped down the decker's cyberdeck and discovered that the hot new AI that Renraku had cooked up had been hiding there at Ares and had jumped on-board the deck! This led to a white-knuckle round of negotiations, the runners trying to survive and get some sort of profit out of it all. Finally, the runners were cornered in an armored bus with the finest from all the Big Ten of megacorps all pointing live fire in their directions, when the AI jumped the deck, shut down most of the telecomm, the corp panzers on-site, and gave the runners a fighting chance to blast themselves out of certain death. The AI revealed itself to them a week later out of the blue, offering them a nice little bonus for having liberated it. Good times, chummer, good times.