Numerous motherboards removed when upgrading my PC and kept in case I ever needed to build a really slow computer.
Even more IDE hard disks, in case I wanted to revert to less storage.
The ISDN stuff that came off the wall when I graduated to broadband, in case I wanted a slow, expensive connection for my downgraded PC.
A Vodafone PCMCIA card.
A Bluetooth dongle.
And tonight's star prize: a Digital Equipment SCSI tape streamer and a collection of DLT tapes, some containing backups from the last millennium.