Why should we just learn from our good experiences? We can learn from mistakes!
So here's my (incomplete) list of RPG situations that should grant XP to anyone who survives. Treat it as a suggestion list: sometimes it won't be right to give out a reward, even though the failure is on the list - and other times, something that's not on the list will totally deserve some compensatory XP.
Some of these listed failures are conditional on the situation being deadly. This means that you should actually be fighting for your life, rather than sparring with your allies.
Some of these are for first times only - the first time a bad thing happens to you, you get to learn something from it, but when it happens over and over again, not so much. There's two reasons for that: it's simpler, and it'll stop players from doing it deliberately.
That's a very important point - if you find yourself with players demanding XP for deliberately stupid actions, then you'll need to revise your decision on using this houserule.
How much XP should be gained from these failures and mishaps? I propose that it should be 10% of the XP you gain in a session. Not much - but it all adds up...
- Any time a party member dies (unless you killed them - then you just get the usual XP for defeating them)
- First time you get hit in deadly combat
- First time you fall victim to a Combat Manoeuvre in deadly combat
- First time you get knocked out in deadly combat
- First time you fail a saving throw of each type in a deadly situation
- First time you get poisoned
- First time you trigger a trap
- First time you get charmed or dominated by a monster
- First time your method of attack proves to be useless (due to immunity, damage reduction, etc)
- First time you encounter a creature of each type (i.e. aberration, construct, dragon, etc - but NOT animals)
- First time you take damage from falling
- First time you fail a skill check that you would have made if you took 10