I don't feel like listening to anything right now, so I'm going to talk a bit about a band piece we're playing this weekend.
This piece is in the Passacaglia form, and the basis is a melodic line that is based on the tones B A C and H (in English that B flat, A, C, and B natural). There is no other clear form in this, but there is a basic goal of the piece, which is to make a big crecendo from a very light texture to a wall of sound by the end of the piece.
And being a very modern composer, Nelson has many creative ways of adding new voices to make this crecendo. The inital texture is light with the low voices carrying the melody with some additional soft gong and bass drum hits that help establish the mood (the melody is based on four chromatic neighbors, it can't be very happy). Nelson makes good use of rhythmic structure to help the crecendo. In the middle section there are sixteenth notes in the mallets (he even uses the bell tree as a "mallet" instrument which is pretty cool, you can't hit actual notes, but it gives a nice effect). As the piece gets closer to the end there are two drum parts that come in doing sixteenth note triplet and thirty second note figures that really help to thicken the texture, especially when the two parts are doing these two rhythms against each other. The piece finally comes to an end with the winds playing the final note for about as long as they possibly can. I like this piece because it has a fun drum part and it shows a ton of different ways to vary a passacaglia.