Tricky to do, but I solicited one from him quite recently.
The guilty pleasure of conversing with Pats is seeing if you can actually work him into a state of sheer frenzy, to the point where he'll do something radical like use an exclamation point.
I've also seen a spelling mistake or two but again, they're collectors' items.
As outrageous as it may sound, I've also witnessed a smilie in the past. But I think it was just an experimental phase for him. Think he's of the school that believes using a smilie is a bit of a cop-out, why use one when you can get creative with words? Moreover, not using one helps to perpetuate a sense of ambiguity in his thoughts. eg. 'Is Pats being ironic here or does he really believe this stuff?' It all adds to his enigma. Which he quite enjoys, I expect.
:\pimp3: