Blast from the Past

I went to an alumni event today. There was a guy, O; he looked familiar, and then it clicked. He is one of the guys I've been emailing from eharm. Wasn't sure what to do...do I say something? So, we had a moment where we were sitting alone, and he says..."we've met before". And I quickly acknowledge that yes, I know him. He says that we lived together...what? Well...it turns out that he lived in the apartment above me and my roommates back in the college days. The only reason I remembered them was because I dated his roommate. At least I remembered the roommate, but honestly I didn't remember him. Then I whispered, no I'm "X" from eharm. He was confused at first...then I explained how I use a different name when I'm online. We chatted the rest of the afternoon off and on. I really don't remember him from undergrad days. I've such a bad memory for these things. Wow...really..So, we'll see where, if anywhere, it goes. He's not really my type but I'm "desperate" and open to anyone.