I've just put together a ZigBee-based network.
It's been said that it's the little things in life that make the biggest difference (or something like that). In my case, it was pretty exciting seeing a few LEDs blink on a pcb.
I've just put together a ZigBee-based network (using a development kit supplied by Freescale Semiconductor). While it took some time to get the network up and running, I finally did get it to work.
Unfortunately, I didn't have the time to get it to do anything more useful than that. But obviously, if I can get the LED to blink, I could have connected that sensor to something more in line with what the network is actually designed for.
If you're considering designing such a network, I suggest you get in contact with Freescale and get your hands on one of these kits. You'll have your LEDs blinking in no time.