This is a character creation system and play style that I designed to accomodate a large, randomly attending group of players over a long time period. The system uses accelerated leveling, short, difficult campaigns, and relies heavily on Icon bonuses saving and rewarding the characters. I'll link to some of the micro-adventures later after we've played them (wouldn't want to spoil anything!)
The first hour is dedicated to character creation for those who have NOT played yet (there are always new players jumping in).
The player choses their character name, race, class, unique thing and icon (I have the single page icon description available for them to choose from). Players make note of their racial bonuses and abilities for later play.
Ability stats they roll a d10 and are assigned "prerolled" stats from a chart of 10 options that are a pretty even spread. Once those are assigned, they add their race and class bonuses and calculate modifiers AC, PD, MD, Inititative and hit points.
I asign gold, silver and bronze base don a roll (I have 2 gold d10, a silver d20 and bronze d6. The gold is awarded as lowest number, hightest number example: a 4 and 3 would be 34 gold, a 0 and 2 would be 20 since 0 is a 10, etc)
Backgrounds, waepons and attire are awarded through creative story telling. I usually start each session descrbing the scenea nd ask each player to describe their character. Didn't mention your weapons? You'll have to find something in the environment or kill and steal. Didn't describe your elaborate armor? Its assumed its basic.
I have "quick sheets" of class feats, talents, spells, etc (there are several great ones in the Vault, look around!) that I pass out each session for reference.
For battle, I have them tell me what they want their character to do, then help them decide how that translates into a talent, feat, spell, etc. This means as they play more, they are accumulating these skills as needed and tracking what they use on their character sheet. This means the game master has to be pretty familiar with most classes and abilities to guide newer players who might not be familiar wiht termonology or what their powers are. It relies heavily on improvisation and good storytelling by the players as well, as I am generous with difficulties in a "Swashbuckler" kind of way:if you amuse me, I'll make it happen.
The current system for leveling is 3 game sessions equal a level up. Each session/story they are assumed rested and healed. As I can have up to 10 players at any given time and people will miss sessions, I try to have quick, compact campaigns that can be done in 1.5-2 hours. Generally this means intro, battle, puzzle or quest, final battle, rewards. I have a series of campaign outlines around different regions and icons (I will post some of these as they are played), that I choose from based on icon rolls at the start of each session. This lets me offer some great rewards and found items along the way, as well as keep things moving if the rolls just aren't happening.
Overall, the system allows people to stop in as they can, without feeling like they aren't making character progress. It alows a lot of character conversations and creativity. Could be used for conventions, monthly game nights for large groups with not a lot of time, etc. Its a little more fun than using pre-gens and gets you right into the game quickly.