"Give us a song, Tristram," More than one person looked twice. Guenevere hadn't gotten on well with Tristram since the Cornish knight had been made acting first officer during Lancelot's leave of absence. Perhaps the budding romance between Tristram and Isolde had melted her heart toward Tristram - especially since Isolde was also married to a king but Tristram had yet ever to abandon her in order to train a son by another woman ...
"I can't, my queen." For a moment it seemed that resentment on Tristram's part would override knightly courtesy, but Tristram had a genuine reason for refusing. "I have no harp." It'd been damaged, rocking around in Tristram's quarters during their last battle.
"Use Sir Dagonet's," Arthur suggested.
"The jester's?" Tristram scowled at the idea, then turned to scowl at the harp itself in its case in a wall of the dining room. "It's second-rate - made from a holly tree."
"Not up to the challenge, are you?" said Kay amidst supervising the DWARVes and servants clearing the dishes.
The stick at Tristram's pride worked, even as obvious as it was. The Cornish knight got up, took the harp from the wall, and struck a chord.
I sing the tale
Of hero and lion -
The chord struck back. The harp's initial notes and all subsequent were so out of tune that everyone in the room winced. "I yield! I yield!" cried Kay in defeat.
Point made, Tristram retired the offending instrument back to its case. "Trust holly wood to ruin a good story."