(and it's driving me crazy!)
My cell phone. Which I hardly ever use. Last seen on the shelf by the front door sometime during the Christmas season. If I don't find it soon, really soon, and charge it up with credit (which I suppose I could do without actually finding it — hmmm...), I will lose my phone number. I don't understand the ubiquity of the cell phone when the terms and conditions of using one are so inconvenient.
My daughter's birth certificate. Which we'll need in order to cross the border, to enjoy a planned kind-of-roadtrip, 2 weeks from now, in which the kid and I will be dropped in DC to hang with my sister. I can see it in my mind's eye — it's in a plain white envelope along with the letter from J-F granting me permission to take her cross-border; I came across it relatively recently, in a pile of documents it shouldn't've been filed with. I cannot remember if I left it there, or filed it someplace I felt it more logical to be; but it is in neither of those places. We've applied for a replacement.
My Diagnostic and Statistical Manual of Mental Disorder, 4th edition, desk reference. It used to sit right beside the American Psychiatric Association glossary. I know I used it, for reference, last spring. My boss last week asked me if I was familiar with it, would it have the info required for one of the projects we're working on, maybe we should get one for the office. I offered to bring mine in. I've spent far too much time looking for it. We've ordered a copy for the office.
The slipcover of the complete third series of Doctor Who on DVD, the one with the Doctor and Martha pictured. Deep down, I don't really care where it is, but it bothers me that I have no idea what happened to it. (What do people do with those covers? Does anyone actually slip the DVD back into it? Throw it away? I have a squashed stack.)
In a general way, I'm bothered that I'm unable to find (to buy) a replacement for the black beret with the black embroidered stylized flowers that I lost a few months ago, between my office and the metro, all of a 2-minute walk, indoors. Months ago, and I'm still bothered.
I always know where everything is. More than anything, I'm bothered by these lapses in my attention.