Non-gamers be warned. This post is really crunchy.
Experience Points, or XP is one of the more common metrics for tracking a character's advancement and power gain in a roleplaying game like D&D.
In D&D characters gain XP for killing monsters, completing quests and doing otherwise awesome things. When they gain enough, they go up a level and get a bit beefier. This system works well enough, but has some definite drawbacks.
First off, at least in 3.5 edition D&D, the only clearly established method of assigning XP is to dole it out according to an encounter's challenge rating. The only hard and fast rules for determining an encounter's challenge rating are based on how hard a particular monster, or trap is to defeat. Ergo, the only cut and dry method for assigning XP is related to encounters where the players beat up a monster, or disarm a trap. Well, what about all those other encounters? You know, like the ones where they roleplay?
Truth is, assigning XP for non-combat encounters is pretty ad hoc in 3rd and 3.5 edition D&D. 4th edition introduced non-combat skill challenges as a way to create a non-combat encounter with a clear challenge rating, but this system also substituted dice rolls for time that would otherwise be spent roleplaying a character. Instead of the players trying to convince the stormtroopers these are not the droids they're looking for, they let the dice do the talking.
Over the past several years, I have managed to kajigger (technical term) a system, by which I can assign XP for non-combat encounters in a way that I feel helps keep their rewards on par with those gained through stabbing things with claws and teeth. Here's how it works:
First: I determine how important and/or dangerous a given encounter is. If it is directly related to advancing the main plot, or if it could potentially devolve into combat if handled poorly, I assign it an XP value equal to the party's level. If it is not as important, I give it half that amount. HOWEVER. Because my group is larger than the baseline 4 character party 3.5 edition is built around, I make sure to give each of my players the equivalent of the xp / 4 for roleplaying, puzzle or other non-combat encounters. I do this, because, while having an extra sword arm might make a fight less difficult (thus worth less xp per person) it does not necessarily help with roleplaying or problem-solving challenges.
Second: For encounters that rely heavily on the actions of one particular player, such as the rogue for disarming traps, or if one player does all the talking or puzzle solving, I typically give the active participants full points and the passive party members 1/2 points. Why give the non-participants any XP at all? Mainly to keep the group fairly close in their advancement. Balancing an adventure for characters with a broad range of levels is a real pain in the butt!
Third: I give bonus XP for awesome roleplaying. I typically dish this out to one or two characters per session. The total bonus is usually 10% of the XP total for the night, and I make sure to let my players know who got it and why. This encourages them to dance for me like the greedy XP monkeys they are. >: )
Fellow GMs, how do you go about rewarding your players for stuff not otherwise covered in the rules?