Just play the trombone, that's what I play. It's a whole lot of fun. But other band instruments include: Trumpet, Tuba, Baritone Horn (AKA euphonium), French Horn, Clarinet, Flute, Oboe, Bass Clarinet, Alto Saxophone, Baritone Saxophone, Tenor Saxophone (if you choose Saxophone, pick Alto. I recommend that if you want to change to Tenor or Baritone sax, wait till 7th or 8th grade). There's also percussion and bassoon. Orchestra instruments are: Viola, Violin, Cello, Bass. That's all I know for orchestra but I recommend band!
I was in the 'percussion' section in middle school. They taught you all the instruments within that specific section, but I played the snare drum because it just plain rocked! Plus, percussion is like the beat of the entire band/orchestra :D