* Alexa, call my phone (because I can't find it)
* Alexa, call for Chinese food (okay everyone call out what you want)
* Alexa, send a message to my son -- "I've fallen and I can't get up"
Once it is set up, you can say, "Alexa, tell Trackr to find my phone", which will tell you the address your phone was last seen. You can also say, "Alexa, tell Trackr to ring my phone", which will make your phone ding even if it is on silent.
The "Help! I've fallen and can't get up!" functionality can be had by installing the "Ask My Buddy" skill, which will let you designate emergency contacts which you can notify by voice.
It's not chinese food, but both Dominos and Pizza Hut now have Alexa skills available which will let you order by voice, as well.
In the UK, Just Eat has an Alexa skill - they're one of two major "takeaway aggregators" here.
* Alexa, call the living room: hey everybody, dinner's getting cold!
Allow drop in between your devices in your home, and you can call one from another. Maybe they'll allow call groups and you can call to every room at once.
Third idea is really interesting though, maybe calling the emergency services could be good in that situation too
I tinkered a little bit with this idea when the Echo Dot came out, but these limitations more or less killed my interest in exploring the concept further.