I have one good and one bad (but extremely funny) story that come from the same campaign. This was a pretty big group, with eight players meeting every week. Everyone in the group was very experienced and we were able to change DMs every adventure. When a player graduated to DM, his character would either “Go rest at the inn” for the duration of the game, with the assumption that he would recieve his fair share of loot and experience upon the adventure’s end. This was a fairly fast-paced game with levels typically coming every two or three weeks, which meant that we would occasionally get hilarious multiclassed characters who had cowboy-ed up and taken stuff completely unrelated to their role in order to make up for the DM’s character swimming in their cups rather than helping out.
The most memorable example of this was one of our arcane spellcasters, who was agnostic and loudly outspoken about it, much to the in-character annoyance of our healers. Shortly after our healer became the DM, the sorceror took several levels of cleric, and the sudden, direct evidence of the existence of divine beings apparently shook him up. The poor fellow began to manifest an OCD-like tick where, whenever he was forced to cast a divine spell (and he was a good healer; he never skimped on the healing magic) he would immediately follow it up by performing a number of strange and increasingly alarming and rituals as a means of worshiping his non-divine, non-magical, very decidedly mundane spellbooks.
One day, following a particularly rough battle, he was forced to expend a number of healing spells to patch us up. We were close to full-up at that point, and instead of spending the day resting the party decided to search the city for information. Our sorcerer was having none of that, however, and his player (with a unsettlingly mischievous glint in his eye) had a quick, whispered conference with the DM, after which he asked the group if his character could stay at the inn. We had no problem with it, and we tried to keep our inquiries in the city short in deference to his decision… but no sooner had we turned back towards our inn than we ran into a squad of extremely dirty and worn-out constables who had our sorcerer in tow. Apparently he was worried that all the divine spellslinging had offended his spellbooks, and the moment our group was out of sight he had set about conducting a number of rituals devoted to “The almighty lord Keros, conqueror of shadows and patron saint of oil lamps”, which apparently began with setting the inn on fire and ended with his levitating above the balcony, using a telekinesis spell to douse passing citizens with lamp oil and a second spell to animate several books of matches that he sent chasing after said citizens.
Rather than immediately free him from the guards, we escorted him to the police station where our faceman (a rogue-type halfling whose charisma added up to 27 when you factored in all of the enchanted items and spells we routinely dipped him in, and who our group had unanimously dubbed “the sexy midget”) convinced the magistrate to set our sorcerer free based on a number of hastily-forged religious documents that we’d scrawled up while en route, which appeared to prove that Keros was a real deity whose religious observations involved setting people on fire, as “True believers will rise above the flame”.
The thing is, our sexy midget did far, far too good of a job: not only did he convince the magistrate of Keros’s legitimacy, but he also convinced every single onlooker in the station. Word quickly spread, from one jurisdiction to the next, and we couldn’t seem to go anywhere without civil service types begging our (by this time, apparently quite insane) sorcerer for sermons. Finally, a local organized crime syndicate got wind of what was going on and chased us out of the city, province, and pretty much the country, as the converted bureaucrats had apparently, on a whim, set fire to a local capo in order to bless him when he went to deliver a bribe.
The best part of this entire sequence, however, came several sessions later as the current DM’s adventure was winding down; apparently, when he had become a healer our sorcerer chose to worship a god of trickery who granted increasingly powerful stat and spellcasting bonuses on adherents based on how grandiose a lie they were capable of foisting off on unsuspecting individuals… apparently his god was so impressed by the sorcerer’s ability to legitimize pyromania as a form of religious practice that he had decided to convey divine abilities on he and the rest of the party.
So for the rest of the campaign, everybody in our party had the divine ability to ignite practically any mundane substance by touch, and to suffuse themselves or a target within melee range with a fire shield that did one point of (resistible) damage every round to enemies that were within range. However, both abilities came with a drawback: in order to keep any fire started in this manner burning, the character involved had to loudly praise and worship the fictional deity of his choice at the top of his lungs. Every onlooker that was convinced by his performance conveyed bonuses onto the blaze, which meant that you could get a positively dangerous conflagration going with enough people. (Sometimes, when we were feeling particularly vindictive, we would lure enemy forces into the province where this all started; there’s nothing quite like starting a fire around the bad guys in a city full of Karos worshippers or, as they prefer to be called, “Karos-ines”.