What's the rarest or most unusual computer-related item do you own?

A few more things I have, that I just thought of. A plastic brightness control knob from an IBM 5110 portable computer. I removed this a few seconds before I was tasked to smash it and half a dozen others to bits. First thing to be done was to 'de-louse' the CRTs by knocking the glass pip off the end with a screwdriver, then check and remove any capacitors that might have contained PCB, to be placed in a tough plastic bag for incineration. I don't recall if the 5110 had any caps like that, but other old equipment did. This was back in 1982, I was doing work experience at IBM and we had to scrap a pile of (financially) written-off gear prior to going to the scrap metal place. I also got a 3330(?) head. I have never gotten over the 5110's to this day. Bill Gates autograph. Bill was on a visit to Sydney back in the early 90s to spruik Microsoft's involvement with IBM in working on OS/2. I happened to be sitting in the front row of the auditorium and when he finished speaking, his 'minder' the CEO of Microsoft Australia immediately ushered him to the doors. I reached into my work bag and grabbed my well-worn copy of the Windows 3.1 Developers Guide, a pen, and ran to the door. I shoved the book in his face and to the annoyance of the CEO he graciously signed it 'Best Regards, Bill Gates'. :) IBM 3420 tape drive. I threw a low bid on this, expecting to be outbid. It was getting near the end of the auction and I was having second thoughts about it, as it was two states away and I had found out how much these things weigh. I was desperately hoping to be outbid but I ended up with it. The seller wanted it 'outta here' between Xmas and New Year, so I then had to get it shipped interstate in that period, and I was away from home to compound the situation. I managed to do get it done using a furniture backloader, those guys almost did their backs in trying to unload it at my mother's place, in the summer heat. She gave them a beer for their efforts. Steve.