Yep. Still kinda' mad about Aliens: Colonial Marines.
Before I vacated the UK, a surprisingly large proportion of my social circle consisted of aspiring stand-ups. This is relatively unusual; while plain-old fiction writers tend to flock together for warmth (both metaphorical and literal if they're unpublished) comedians generally go out of their way to avoid one another. We're attention seekers by nature, so put us in a room with another comedian and the subject will quickly shift to, "who can tell the best joke," soon to be followed by, "who can wield a shank with the most precision." We also live in perpetual fear of fellow professionals stealing our material before we can use it and stake a claim to it. This doesn't happen as often as you'd think. Banter generally doesn't produce much in the way of usable material. But when it does produce the occasional gem, God help you if you don't have a system for divvying up the spoils.
In my circle, we used what we called "the rule of conquest." Essentially, if someone tells an unpolished joke and one of the listeners manages to produce a better punch line (bonus points if they do it before the original punch line has been delivered), the latter can lay claim to the joke. The original joke owner cannot, however, use the improved punch line in their own material - at least, not without attracting the ire of the group.
Of course, there was a special degree of hatred reserved for those who one-upped a joke then didn't use it.