Buffy is the secret queen of the universe and she and Tara are actually sisters--maybe instead of Dawn appearing in season five, Tara is suddenly her sister and is living in the Summers house, and seems to have a sinister evil plan, but we don't know what it is yet. Run, Willow, run!
Spike is in a band with several of his vampire brothers and sisters. Um, no.
Spike and Xander are astronauts! Spike and Xander are exploring the outer ridge of Mars, trying to find a new strike of some mineral that will make them rich beyond their wildest dreams. Mars, prostitutes, old western themes, big leather boots.
The sewers of Paris. Sewers with all sorts of hidden tunnels, a hidden city beneath Paris--or Sunnydale, Sunnydale. And there are layers and layers of cities down there and one day Buffy stumbles and finds the way in and liberates the lost children of...whatever.
Spike grows a giant pair of wings. And keeps flying around and getting caught in trees. He won't come down. They tempt him with cheese. Bloody cheese.
Willow is dating a werewolf then gets bitten by a cougar. She turns into a werecat. Hijinks ensue.
Tara and Willow and Xander have an icky, icky threesome and run in terror the next morning and never speak to each other again. Xander becomes a monk.
Damn. My five minutes are up. Five minutes go way too quickly. Maybe after breakfast I will try ten minutes.