For those that were asking...
Lulz = bastardisation of LOL.
Therefore to do something for the lulz is to do it for your amusement. Legend has it that pretty much every action in life can be explained or excused if you state afterwards in a loud, clear tone of voice (or just type it, since so many lulz originate on the interwebz) "I did it for the lulz".
Example: raise from early position with 62o. Call when one of the blinds shoves with QQ, suck out on the river and take their chips. While in general this is a bad play, if you respond with "I did it for the lulz" while the other player is abusing you it automatically becomes the best possible play you could've made because you've hit the trifecta - you've got a tilted opponent, chips and lulz.
Another little known fact is that "I did it for the lulz" (IDIFTL) is the greatest legal defence known to man. Not even Alan Shore and Denny Crane can argue their way around it and if Bill Clinton had've employed it instead of his second rate advised-by-expensive-lawyers defence he'd still be president to this day. True story.
Thus endeth today's lesson in internet lore *nods*