Yup - all this sounds very familiar :-(
(a) My A2000 recently died - one of the diodes popped, and gave out a smelly wisp of smoke.
(b) I've (mis-)connected a power lead to a floppy drive - offset by one pin. The wires melted together into a stinking mess. The drive still works, though! :-)
(c) I've destroyed an old A1200 memory card - sparks and smoke everywhere! The A1200 is OK, but the card isn't (obviously!)
I don't think that I've done much else that's too stupid - a lot of the mistakes were from trying to fit things into a towered A1200... not very good visibility, difficult to move around and align things... recipe for disaster :-)
