I'm not sure I ever wrote up anything about house rules beyond a few bullet points in an email, and there are a few rules I'd like to share. Details follow, so read on if you're interested. Better late than never, I suppose...
Stats generation for characters uses my standard roll of 4d6 and drop the lowest die unless it's a 1, then assign as you see fit. Yes, that means you can roll a 19 in a stat with three sixes and a one, and you average slightly higher stats than normal. It's not a huge imbalance, especially given the overclocked power level the party has earned over the years.
I punted supplements in general after the mass of splatbooks started feeling like an arms race, and I eventually ran the game almost entirely from the System Reference Document. I was so trendy, I had the entire SRD available on my Palm - if only the search time was faster... Since I used the SRD, prestige classes didn't come up often at all, though I used the Assassin class to death when updating The Assassin's Knot. I'd rather stick with a base class and model your idea of your character's abilities using feats, swapping class abilities, and outright adding cool stuff. I've tried to be consistent over the years, and I hope I managed to pull off at least a workable balance.
Quirks and Flaws
Everybody got a chance to pick a drawback or quirk in exchange for a little power boost that made sense. Wulfgar latched on to hydrophobia and eventually got paid back with weapon bonding to his axe that gains power as he levels. Asalia took "locked up by her father which caused some psychological issues" and got paid in wonderful role-playing opportunities. Pandora's quirk was her compulsion to make Trail Mix (now with Real Trail!). She'd make a batch in the morning out of whatever ingredients were handy, then roll a d20 to determine roughly if it was good or bad. Anyone eating the Trail Mix rolls a Fortitude save and has something minor happen - usually a +/-1 to a stat or a save, and possibly dry heaves. Given the fickle dice at the table, Wulfgar eventually swore it off since the Dwarven Fighter couldn't make a Fortitude save to choke the stuff down.
Character quirks give you hooks to make play more interesting, and I highly recommend using them for any character.
When starting out with a Paladin in the party, I needed to get a handle on "Paladin Radar", otherwise know as the Detect Evil ability. I made a couple of changes which seemed to work out pretty well. First, Janik's eyes would burst into flames when he used it, so everyone around him knew every time it went active. Second, I changed it to Detect Motivation to introduce some grayness to play in.
I wanted to give more detail than a simple "it's evil so you can kill it" answer to handle situations like a good person doing evil things to save their family. I wanted the character to make the call, not me acting as their higher power. So I let Janik see into people's hearts and get an impression of a person's motivations rather than just see the taint of evil. I think it worked out really well, and Janik still got to use his Paladin Radar to chase down goblins in the middle of a blizzard caused by a white dragon.
Upgrading to 3.5, or "The Magic Ty-D-Bol"
Wizards had the unmitigated audacity to upgrade the rules to 3.5 while the campaign was running. It smoothed over some rough patches in 3.0 and added some things I liked, so I decided we should probably switch over. But the spell nerfing in 3.5 needed to be explained in the context of the game world, so I made an adventure out of it.
The party discovered that the drow were doing something magical and nasty. They decided to investigate. Eventually they found a room filled with a swirling vortex of arcane energy being attended by several drow wizards. It seemed to be sucking the magic out of the surface world and storing it in the Underdark for later drow use. The party immediately dubbed the vortex "The Magic Ty-D-Bol", and it stuck from that moment on. Since most of the party cast spells, this vortex simply would not do. True to form, Asalia tied a rope around herself and flung herself into it to disrupt the ritual. It worked, but not before the nature of magic changed and reality along with it.
Voila! New rules implemented with an in-game reason to make the change. It satisfied me immensely. I don't think I can pull the same trick with an upgrade to 4E - the structure of the rules has changed a little too much to do it without recreating the characters from scratch. We'll finish it out in 3.5 and move on from there.
As a Priest of Odin, Thorolf could use runes. He could easily cast and read runes as an impromptu Augury effect once a day. In some cases we actually pulled and interpreted runes during the course of play. My jaw dropped at how well the random pulls actually fit the situation and the question every single time.
He could also scribe runes to enchant items for specific purposes. The permanence of the item depended on the materials he had to work with. A simple Alarm spell for a night could be scribed on the wall with chalk, but if you wanted that flaming spear to last more than a single hit you should probably invest the money and rework the spearhead to hold the runes permanently. He had a pool of uses per day which he could use to power effects, including permanent items. Eventually he could wean the permanent items, but he would be down a few slots while the enchantment took hold.
I modeled this ability by creating a Runecraft feat which gave access to the Int-based Runecraft skill. He'd need to make a skill check any time he wanted to kick off a power or enchant an item or create his boat. It fit easily into the existing system, and I could dovetail runecraft uses into the item creation rules with no problem at all. I typed it up, and I probably should have submitted it to Dragon at some point. I didn't, and someone else published a take on runecraft for 3.5 in Dragon. C'est la vie.
Ignoring Spell Failure, Swapping Elements, and Other Options
I introduced Spellswords into the game when they rescued a Rugathi Spellsword from the Steading of the Hill Giant Chief. Rugathi are also known as Red Elves. They only live about 200 years because they don't need to sleep, trance or rest at all. The Spellsword trained Wulfgar on working spells while wearing armor and tying a spell to a weapon so it would detonate on a melee hit. Both manifested as feats.
Early on the party investigated a summoner's tower that blew up just oustide Adris. They discovered mephits guarding his underground complex, some mad, some reasonable. They managed to Dismiss most of them, and they even met up with Icy and Steamy much later on in the game. It took some time, but they deciphered some notes and found a metamagic feat that would let spellcasters swap elemental effects on the fly for +1 level. I allowed swapping in Force effects for +2 levels since there's no Resistance to Force anywhere. Did your sorcerer learn Fireball, but you're headed to the Plane of Fire? No problem! Cast it as a 4th level spell and make it an Iceball, or maybe a 5th level Forceball.
Generally, I think I'm pretty flexible as a GM. I believe that the rules should support the game and not limit it. If you want your character to have an ability, let me know and we'll work something out.
I'm still going through the pile of loose notes, the box and a half of home-printed index cards, and the two notebooks to get up to speed on Adris and The Bickering Eight. I'm sure I've hacked the rules in a few other places. If so, it'll come out in future posts.
Thanks for reading!