Today (29 May 2013) is the 100th anniversary of the first of performance of Le sacre du printemps (The Rite of Spring, music by Igor Stravinsky, choreography by Vaslav Nijinsky, and scenic designs and costumes by Nicholas Roerich). The Rite has been a touchstone for artists (of all kinds) and audiences (both pro and con) ever since.
So much has been written and said about the Rite that to say anything at all about it is to risk cliché and truism. I'll jump in anyway, to say that every page of this score contains miracles and wonders of invention in every aspect of the art and craft of composition. In instrumentation (the instruments used) and orchestration (how they are used) this piece (and others, to be sure) sent the 20th century on its colorful way. The beginning of the score is an illustration of Stravinsky's imagination in this area--the high C with which the bassoon opens would not have the same yearning quality if played on an instrument (the clarinet, for instance) in whose range the note more comfortably lies.
Rhythm in the Rite gets discussed, analyzed, marveled at, and imitated. And deservedly so. Related to rhythm is form/structure. If rhythm is the interaction of sound with time on the local, micro level, form/structure is the interaction of sound with time, on a global or macro level. The Rite is a ballet that tells a story, so the form of the music must reflect that to a certain extent. Stravinsky builds his scenes through the repetition, in different instrumental guises, of short, immediately recognizable melodic fragments, over layered accompaniments. These usually build and build in intensity until they break off and the next section begins. Throughout his career, regardless of the surface style of his music, Stravinsky used this cinematic technique, like cross-cutting between stories.
There are a few pieces, movies, books, etc., which I almost wish I could go back and experience for the first time again. This is one of them.
 It's worth noting here a practical value of Stravinsky's innovation, and innovation in general. That high C was thought to be virtually impossible for the bassoon to play the way Stravinsky asked that it be played; today, any reasonably good high school bassoon player can sound it with ease.
 See the Symphonies of Wind Instruments (1920) for a more thorough-going use of this technique in a piece that is, on the surface, radically different from the Rite.