Not the same, but still funny:
A customer had bought a computer from us about a year ago and a Voodoo 3 card just yesterday. He took it home and tried to install it but couldn't, so he brought them both in this morning. He ranted and raved, etc. He had reboxed the Voodoo 3, expecting a replacement, so we took the computer and the Voodoo 3 in the back and told him we would fit it for free. When we opened the box for the Voodoo 3, it was in a terrible state. The bit of metal that attaches the card to the case was taken off, and a wee heatsink had been scraped off the chip with a screwdriver. I reglued the sink and reattached the backplate. So we opened the machine, and tried to fit the card. Ack. Card is AGP, computer has exactly zero AGP slots. So we went back to the front.
* Me: "Sir, your computer has no AGP slots, and this is an AGP video card."
* Customer: "Yeah, but the card fit perfectly into the little white slot."
* Me: "Which white slot?"
* Guy: "There's five of them -- little white ones. There's a spare one."
* Me: "The PCI slot? Uhh...it shouldn't...let me check."
Sure enough, if you remove the heatsink and backplate, turn the card around, and really hammer it into the only free PCI slot, it will just fit snugly next to the hard disk.
We explained that the AGP card was completely destroyed and he had voided the warranty on it by hacking away at it with a screwdriver. The usual mad customer vs. techie exchange ensued, but he eventually backed down and bought the PCI version instead...and got us to fit it.