Show all of the photos belonging to one user that another user has marked as a favorite. You can use each person's username, email address (used to sign up to Flickr), or user id.
Motivator, Warholizer, Magazine Cover, Mosaic Maker, Movie Poster, Jigsaw, Hockneyizer, FX, Map Maker, Favorite Surfer, Mat, Pocket Album, Sunset, Badge Maker, Top Cameras, Calendar, Trading Card, Framer, Wallpaper, Palette Generator, Cube, Bead Art, Guess the Title, CD Cover, Random Photo Browser, Captioner, Lolcat Generator, Billboard, Photo Fortune, Slideshow, Writer, Blog Header, Gallery, On Black, Profile Widget, Scout, Flickr DNA, Name That Contact, Favorite Finder, Pool Cleaner
I know, right? It's a lot to take in. Go slow.