I'm doing a big paper in Symphonic Lit about this piece so I thought I would talk about it a little on the blog.
The entire movement is based on the motive that is entirely in an Eb arpeggio that goes do-mi-do-sol-do-mi-sol-do. Beethoven employs many different strategies to extend this very short amount of material for over fifteen minutes. One of these strategies is taking the motive and trading it around instruments. Another strategy is to extending the phrases. Near the beggining he uses a neighbor tone to extend the phrase for a couple measures. And of course when the cadence is nearing, he uses fast string parts to keep the excitement despite spending thirty seconds just resolving a cadence. The many uses of sequence in the piece are also effective, increasing tension and extending the music for several measures.
Another way of making the music exciting is the use of hemiola in the loud parts, making the piece sounding like it is in 3/2 instead of 3/4. There are also accented off beats that add to the unsteadiness and excitement.