host_vars example ?

[Shawn Mulford]

Hey guys,
First, sorry for what seems like a rather basic question..

I want read in a host_vars file for to dynamically set up the operating environment. I'm trying to start with 1 variable declaration, but keep getting:

ERROR: /etc/ansible/host_vars/somenode/vars.yml must be stored as a dictionary/hash

What is the format expected? I've tried:
key: value
key = value
{"key" : "value"}

Thanks !