I made a simple bash alias for this:

  mknote () {
   emacs -nw $HOME/notes/`date "+%Y-%m-%d-"`${1}.txt
  }

so that I can do:

  $ mknote FooTopic

and start recording things.

I also have enote:

  enote () {
   local newest=$(ls -Ft $HOME/notes/\*.txt | grep "$1" | head -n 1) 
   emacs -nw $newest
  }

to go back and edit them by name.