Very cool stuff: an interactive Tree of Life, with all the phylogenetic relationships you could possibly ask for. It's interesting how the arbitrary (and stupid) system of kingdom-phylum-class-order-family-genus-species, which is what I learned in school some dozen years ago, has been almost entirely abandoned. In its place is a tree that has as many nodes and linkages as it needs to. It's a change from a fixed, rigid classification to a fractal system.
My favorite lineage is Aves, the birds:
Eukaryotes -> Animals -> Bilateria -> Deuterostomia -> Chordata -> Craniata -> Vertebrata -> Gnathostomata -> Sarcopterygii -> Terrestrial Vertebrates -> Amniota -> Diapsida -> Archosauromorpha -> Archosauria -> Dinosauria -> Theropoda -> Coelurosauria -> Aves