BtVS by Whedon and Mutant Enemy. Doctor Who optioned by the BBC. Stargate by Gekko Productions and others.
I had this moderately AU backstory floating around my head for awhile. I want to thank mikerich and his Challenge at Twisting the Hellmouth, listed below, for a very detailed framework to hang it in :)
Xander was walking through the bins of the costume shop keeping an ear on Buffy and Willow's conversation when he was distracted by a woman with a particularly tight top. Not looking where he was going, he bumped into a man who was bent over, putting a box on a low shelf. Something in the box hit something else with an interesting clink, so, dismissing the man with a muttered apology, Xander sat down to investigate.
Among other things, the box held a locket and a silvery thing with a bluish tip that resembled part of a drill or an unfinished screwdriver. Xander brushed aside a rubber chicken and a leatherbound book with arm-straps to reach the items he was interested in and stood up.
"Ahem," the man said. "Those are items I just purchased at a yard sale. I'm sorry that they don't have price tags yet, but I was hoping to beat the rush. That thing opens - you know..."
Xander gave the man a half-smile and snapped open the locket to reveal a brown-haired man with an oddly colored coat and a long scarf. The man in the picture had just stepped out of a black car to climb some stone steps, the screwdriver-thing visible in his hand. Xander was struck by the composition of the picture, so he turned to the man standing in front of him who he figured to be the store's owner - or at least an employee - and began to negotiate a price for the stuff.
They had just finished closing the deal when Buffy walked by with an armload of dress.
"Seems like you know her," the store owner said, nodding after the blond-haired girl. "My name is Ethan, by the way."
"Xander here," he said, thumping his chest. "Yeah, she's buying that in order to impress this... old guy she hangs out with."
"Old, you say?"
"Much older. Sure, the guy has looks, but his personality's much too stiff and-"
"Thank you," Ethan said, taking the young man's money and walking away without so much as a second glance.
Yes, Ethan thought. She's the one I saw with Rupert on my last 'shopping trip'. She must be buying that dress to impress him with demure femininity... Well, far be it from me to pass up an opportunity to screw with Ripper's head.
"I'm sorry, miss," he said from just a step behind Buffy, causing her to whirl around and glare. "But I'd hate to see someone with such a good figure and fine muscle tone covered up in so much lace. I mean, that garment will do nothing but obstruct your movements."
"Sold," Buffy said, thrusting the dress into his arms. "You had me with the British accent. Lead on to the stuff I can fight in."
A short trip around the store gained them the makings of a decent Xena fighting suit. Ethan smiled sweetly as he rung her up. "I'd really love to see the look on Ripper's face when he sees her in this," he muttered to himself just a bit too loudly.
"Ripper," Buffy asked with a rather cute frown on her face. "You know Angel?"
"Angel?" Ethan asked, shaking his head in puzzlement. "I'm sorry, you look like the young woman going out with the bloke I'm thinking of. I must have you confused with someone else."
"Huh," muttered Buffy as she left the store.
"Hmph," snorted Ethan as he returned to his work. He was vaguely disgruntled for the rest of the evening.
Prompted by mikerich's 'Xander Who' Challenge: "Xander sees a sonic screwdriver prop in Ethan's bargain bin for two dollars so, with a smirk, he buys it from Ethan and -