Since Ed is naturally contributing to the raffle portion of the party (and because no one loves a good party like the Playboy), you can bet he'll be making an appearance at the party. Of course, with things like paint wars and artsy stuff going on, things will likely get messy...so he's wearing something he doesn't mind getting splattered and battered. He'll probably end up framing the shirt.
http://charmed.svet-serialu.eu/screen/julian/obr/julian-mcmahon_04.jpg
And hey...did someone say Paint War!? HELL YEAH! And just to make things interesting, he's bringing his own toy instead of relying on those sissy squirt guns...
http://harrierstrike.yolasite.com/resources/FN303.jpg
Don't panic, it's just a paint gun and nothing more - Ed doesn't want to see anyone get hurt, after all, and it's guaranteed not to cause any pain to someone getting hit by a glob of paint. Promise.