The cracking sound it made when the DS went arrse over tit and dropped it down the stairs, breaking the stock and handguard in the process. "That'll teach you to scuff my floor up with your fcuking ammo boots" I thought to myself, as I moved outside to form up for a POP rehearsal.
Not my favourite, but I have vivid memories of being awakened from a dream, about somewhere warm and sunny, by the dull thud of an SLR being dropped.
It was a bit of a shock to wake up and find that it was me that had dropped it and I was actually on a recce patrol somewhere wet and windy in Wales; I'd fallen asleep while standing up. Rude awakenings don't come much ruder.