[WORLD_ENDS_SOON]

Have you tried out the ChucK language? I haven't tried Extempore yet, but it looks like the way they handle timing could be similar. ChucK has a very elegant system for synchronizing synthesizers and sequencers where you can write code in a simple imperative style (within a sequencer you can "wait" until the next note needs to be played). The language runtime keeps all of the coroutines running in sync with a global clock. I don't know of other languages that use this style of timing, so I'd be very curious to hear how they compare.