I just made my first steps with the uasyncio module in Micropython and I'm impressed. Here is a small example how to use coroutines for letting all 3 LEDs on the Pyboard v1.1 blink with different intervals. The resulting code is unexpectedly short but also readable.

import pyb
import uasyncio as asyncio

async def blink_led(led, interval_s):
    """Let the LED blink in the given interval."""
    while True:
        await asyncio.sleep(interval_s)

led_red = pyb.LED(1)  # red led on the pyboard
led_green = pyb.LED(2)  # green led on the pyboard
led_yellow = pyb.LED(3)  # yellow led on the pyboard

# get a new event loop
loop = asyncio.get_event_loop()

# create new tasks for each led
loop.call_soon(blink_led(led_red, interval_s=0.5))
loop.call_soon(blink_led(led_green, interval_s=1))
loop.call_soon(blink_led(led_yellow, interval_s=2))

# run all tasks

For a comprehensive tutorial on Micropython async have a look at https://github.com/peterhinch/micropython-async.