GRAND CANYON. BtVS Intertext/Allusion.
In "The Freshman" a reunited (after their post-graduation summer vacations) Buffy and Xander have the following conversation:
Buffy: What'd you do? What'd you see?
Xander: Well...
Buffy: Tell me!
Xander: Grand Canyon!
Buffy: You saw the Grand Canyon!
Xander: Well, I saw the movie Grand Canyon, on cable. Really lame.
Grand Canyon was a critically panned 1991 Lawrence Kasdan film about the interwoven lives of six modern-day Los Angeleans.