I thought, for a brief bit, that thenewgreen was standing in the same line as me at the gas station the other day. In profile, the resemblance was uncanny. I was going through a mini dialog in my head and decided that on the off chance it was him, I'd stop him as he was heading out and asked if he ever heard of an obscure band named "The New Green." If it was, I'd tell him who I was, make a comment on how small the world can be when we least expect it, and maybe offer to exchange numbers. As soon as the guy turned around and I could see his face from straight on, it was quite clear that it wasn't him. Oh well.
I know. Right? keifermiller has posted a few pictures of himself on here before and he looks the spitting image of one of my old co-workers. If it wasn't for his posts, I'd figure he was him.
I once had a few beers with a bunch of strangers, one of whom I could've sworn was kleinbl00 (despite not knowing what he looks like). I did something similar to your plan - after a brief lull in the conversation I asked "Have any of you guys ever heard of a painting called International Klein Blue?" and when they said no I just passed it off as if I'd been daydreaming about a weird blue painting.