I don't really do journaling on my freetime, but I do it at work.
At every job I get myself a new notebook, couple of pens of different colour and always mark the date before I just scribble through out the day.
Ideas, notes, remarks, todos, pretty much everything.
More than once I've been thankful to myself that I do this when I need to look back at notes and it just helps me organize my head.
I do try to keep it pretty too.