I get quite a few misaddressed e-mails to my gmail address as well. Everything from residential solar install invoices through a facebook account that someone continues to try to recover every couple months for years now I cannot delink (and thus cannot sign up for a Facebook account if I even wanted to with my primary e-mail address short of taking over that existing account in the wrong full name).

The best one so far is I've been on a group e-mail chain from some folks in France (I'm in the US) who organize a skiing trip each year to the Alps. I initially sent a couple "I am not the Phil you are looking for!" e-mails, but they continue to re-add me. I have thought about one day just showing up since I've been "invited" and have all the details for booking and just seeing what hilarity ensues.