Oooh! New idea! PSPGirl, your mention of brothers treating PSP as "just another organization" instead of the fraternity it should be got me thinking...I've seen this attitude in some of my brothers and then seen it drastically changed. Most of the time, this was because they went to an interchapter event or to convention, somewhere where there were a LOT of brothers and they got a chance to really feel connected to the fraternity. Maybe if you encourage some less active brothers to go to interchapter events, they would feel more connected to PSP as a whole? Then I bet attendance at chapter events would increase too! Or maybe not...but it's worth a try!
Brian -- you say you have 2 PSP houses -- do you have letters on them and everything, or are they just houses where everyone who lives in them is a brother? We have several of those, and right now we're investigating what it takes, city-ordinance-wise, to put big letters on one house.
Disclaimer: It's late (for me), and I've spent all day at my day-care job...the kiddies have eaten my brain so anything that sounds kooky, blame it on them!