The rationale is that the gods watch the players and slip them luck when they put on a good show.
So here are some things that engender a chance each:
- You burned luck this session (this is the most important one, I've found)
- You are voted MVP for the session by a blind vote (my players keep nominating characters for some reason, and the sometimes vote for NPCs. Hurm.)
- You have fulfilled a quest (sub-parts of a quest listed below; they overlap for one chance)
- Cleared a dungeon
- Retrieved a relic
- Defeated an evil
- Saved an NPC in distress
- You did something important to the cosmic struggle between Law, Chaos and Neutrality (overlaps with quests though)
- You have role-played an insanity or curse to a notable degree
- You have done something truly clever
- You leveled up (and didn't already get bonus luck from a high level-up role that my house ruled leveling involves)
- You did something that was obviously a bad idea and survived (Chaotics only)
- You saved someone at risk of almost certain personal peril (Lawfuls and Neutrals only; combat maight not count)
- Faithful obedience to a god or maybe a patron (leveling actions don't count)
- Pleasing a powerful supernatural (fickleness not withstanding)
- You do an in-character report on the last session
- Offending a devil, demon, or god
- Betraying your alignment
- Refusing a patron's edict
- Not spending any luck this session (use it or lose it).