Ok, digging around the boneyard, I have a couple of pedals that I believe were 1/2", with 0.585 or 0.59 flats, so about 15mm.

Ok, grabbed the 15mm... and yep, popped them right off.

Found a Trek 15mm/36mm wrench. Now I just have to remember why I would need a 36mm wrench. Is that for a threaded 1 1/8" headset.... which one doesn't need until one actually needs it?