In my brass band, we usually start rehearsals with a hymn tune to warm up. Hymn tunes make a good warm-up exercise, but not for the drummer: I usually have either tacet or long rests punctuated by pianissimo rolls which are a pig to play from cold.
What can I usefully be doing to warm up while the band is playing? It can't just be quiet: it must be completely silent to avoid interrupting the rest of the band. Even spinning my sticks around my fingers presents too much risk of noisily dropping one.