Welcome to The World of Greyhawk
X Points are awarded individually for the following:
Monsters killed or wounded, awarded proportionately
Magic Items, awarded to the user
M-U spells
Cleric Spells
Thief/Monk Skills
I am not going to detail exactly how many X points are awarded for spells and skills as the amount will vary depending on the circumstances.
If monsters are neutralized by spells then the spell caster will be awarded the points e.g. there is no experience for a fighter killing a monster put to sleep or held etc
If fighters (or any other characters) deliberately allow neutralized monsters to recover so that they can then kill them for the experience, no X Points will be awarded as this is contrary to the spirit of the rule and the game.
I do not award X Points for treasure, the treasure is it's own reward.
Occasionally Bonus X Points may be awarded for achieving a specific objective which would be divided between the party members.
Bonus X Points may also be awarded to individuals for outstanding role playing.