I have currently memorized the honks of all vehicle in the entire world. That's right, I could tell you what any honk in the world sounds like, because it is daily routine here in Costa Rica to honk. Honk at walkers, honk at other drivers, honk at your friends, or honk at your enemies. Honk and bark. Honk and whistle. Honk at a mariposa gliding through the air.
Here are some of my a favorite honks:
A Mercedes truck sounds like an elephant that stubbed its toe. A short quick elephant honk. Mac trucks sound the exact same, and yes if you pull your arm up and down to signal for a honk from a Mac truck, they will honk (apparently it is a universal symbol). You also have your clown nose honks. These honks typically come from the smaller older vehicles. That's really all I can think of right now, BUT you are interested in any other honks please let me know. I will gladly research it for you, as Costa Rica is the number honk research facility in the world.