My players expressed an interest in setting up a page for their in game achievements, I have listed below my draft list (along with un-humorous names), any additions would be greatly appreciated.... ;)
Achievements:
BOOM!
(Largest total damage from a single AOE attack)
Skull-splitter
(Largest damage dealt to a single target)
Brick
(Most damage taken in a single encounter)
Butcher
(Most killing blows scored)
Taking names
(Most critical hits scored)
Doh!
(Most Natural 1's rolled)
Sickly
(Most failed saving throws)
WTF?
(Highest attack roll that missed)
Slapstick
(Most humorous killing blow scored)
Wham! Howdy.
(Coolest combat move (by general acclaim))
Silver-tongue
(Best line of dialog delivered to an NPC out of combat (by general acclaim))
Sharp-wit
(Best line of dialog delivered to an NPC in combat (by general acclaim))
Just resting
(Most rounds spent KO'd in a single encounter)
Leader of men
(Most damage healed with an AOE ability)
Medic!
(Most damage healed with a single target ability)
I'd try to make the achievements more easily obtainable by everyone. As it is now, you can guarantuee that the 'most damage to single target' will go to the Strikers, for example.
That said, things like 'most humerous kill', 'most in-character moment', 'most awesome use of action point', 'greatest defining moment', 'best story-spoiler', 'silliest remark', 'worst idea ever', 'best idea ever', 'best encounter circumventer'... stuff like that is fun to remember.
Hm. Would be even more fun if the characters would do this stuff. And they actually made little badges that said 'I have the worst ideas!' and wear them with pride. Or enchant them.
I'm getting carried away... 
Hope my ideas help!
I started this a while back with my group, though it got less enthusiasm that I expected. My current ones are:
A Helping Hand Spend a turn during an encounter to save an ally from a trap or hazard, without making an attack roll (unless it is against said trap or hazard).
Double Whammy Critical twice in one turn.
Explorer Waist an outrageous amount of time pursuing a topic that has very little to do with the task at hand.
Fate Did Not Smile Upon You Use a power to re-roll an attack, and roll a natural 1 on the re-roll.
Finish Him! Land the killing blow on a solo monster
Gygax's Smite
Receive a critical hit from a trap.
Healbot Restore 3/4 of an ally's HP in a single turn.
Punisher Deal over 100 points of damage in one turn.
Ruthless Punisher Deal over 200 points of damage in one turn.
Punisher of the Gods Deal over 300 points of damage in one turn.
So Looooooooooooooooooooooooooooong Defeat a solo monster using only at-will attack powers (utility powers of any type are still alowed).
Wait, I thought they nerfed wizards?
Kill 8 minions with a single attack.
What a Waste! Use a daily attack power and only target a minion or minions with it.
You do WHAT? Suggest an utterly random, pointless, and silly course of action, an have the party actually do it.
these are all neat. i'm going to have to steal some.
currently i'm only using:
First Strike
Bloodied Strike
Killing Strike
Minion Kill
Down and Up [dropped during fight, but recovered before fight concluded]
Tactical Actions [anything that really seems to tip the scales or stands out as uber compared to others in party]
so, i'll have to borrow some of these ideas to add in more XP awards. those three strikes at the top and the minion kill are pretty low in XP reward. it acts more like recognition than a major boost.
the DnU stands at 50 XP. i've played in a game that i earned three DnU awards during one encounter. it was a nice bit of recognition.
i also received Selfless Sacrifice during that encounter for stepping into the square of an unconscious party member to protect him and take some licks.
It seems like there would be a LOT of bookkeeping to keep track of these. Can one of you who have tried this let me know how it went? It seems like you would have to compare every attack roll and damage roll against a handful of achievements to see if it is the new-best in any of those categories.
That's why they're leaning towards the set numbers used in video games.
Here's one
Killed by a Kobold - Self explanatory, Seriously what's wrong with you man?! Take double ressurection penalty, and the penalty doesn't go away till you kill something of your level or higher, and reach a milestone.