Author: Matthew J. Neagley

About Matthew J. Neagley

First introduced to RPGs through the DnD Red Box Set in 1990, Matt fights on ongoing battle with GMing ADD, leaving his to-do list littered with the broken wrecks of half-formed campaigns, worlds, characters, settings, and home-brewed systems. Luckily, his wife is also a GM, providing him with time on both sides of the screen.

The other day, Martin posed a question to me. To paraphrase: “How do I set up a die roll to determine how many encounters I have per day and when those encounters occur?” After some discussion, I suggested the below system, which is based on the Exponential distribution. Since we’ve gotten requests for info on this distribution before and the result turned out pretty neat, I wanted to share. The exponential distribution isn’t a concept that exists in a vacuum. Instead it’s a function of […]


Outside of the comment stream, I had a surprising amount of people tell me they found my Overland Encounter Article useful (Three: which is three higher than usual). Universally however, the part of it they mentioned was the final paragraph and illustration: A brief note on die choice: With a single die, all outcomes are equally likely. The more dice you use, the greater central tendency of your roll, and the rarer the high and low values. Using dice of unequal size on the same […]

The Five Room Dungeon has been around almost as long as RPGs themselves, and has been enjoying a surge of popularity in the past few years as a quick and easy way to build a dungeon crawl.  Interestingly enough, it turns out there are only 9 base designs for the five room dungeon. With so few, it’s very easy to simply grab one of the nine, populate it and run a crawl, but it’s also easy to run the same basic layout multiple times until […]

Martin’s recent article on inking his new GameScience dice naturally led to a spirited discussion about GameScience’s claims that their dice are the best dice available in terms of randomness, which quite naturally leads one to ask: “Is my favorite die fair? How can I tell?” One possibility is to perform a chi*-square goodness of fit test. This doesn’t include any difficult math, though it can be tedious without a spreadsheet program. The purpose of a goodness of fit test (often called simply a chi-square […]

Like Most GMs, you probably find your self wondering from time to time just how competent your players are. Are they the well oiled, expertly min-maxed team they claim to be, or are they a bunch of bumbling monkeys? Luckily there’s a simple mathematically accurate method to test their claims based on simple linear algebra: Start with your dungeon map. Here’s a sample randomly generated dungeon from Donjon RPG tools: Once you have your map you’ll have to decide where the entrance is, which room […]

As a GM, you’ll often have extra ideas that you have no current use for or ideas for some future game. Stealing an idea  from writers, you can write a few sentences about each one (so that you don’t end up stumbling across a note like “junkyard angel and transceiver of the gods” and wonder what the hell you were thinking) on a post-it note and stick the notes on an idea board.  If you like, you can certainly color code them, putting all characters […]

The megadungeon is a historical and exciting campaign model with a simple appeal that’s a convenient platform for pickup games, but building one can be an intimidating challenge. There are probably as many approaches to building the megadungeon as there are approaches to the megadungeon proper. Here is one such approach. Step 1: Start with the “Swiss Cheese Assumption” This assumes that the ground is full of natural caves, passages, burrows, etc… You don’t need this assumption to hold for your entire campaign world, it […]