I finished running a two part fantasy story arc this weekend -- the first part of which was done a couple of weeks ago. I ran it for a group I am normally a player in. It was fun and was not connected to any existing campaign I ran but I ran the story around a basic premise: X-Files meets Fantasy. A very medieval setting... low magic... a demon conspiracy as opposed to the show's alien one. I kept it relevatively 'free-form' and allowed the characters to follow whatever avenues they saw fit to pursue while being mindful of what the various factions were doing in the background. Of course this led to multiple threads and even I was starting to have some difficulties in sorting everything from one session to the next. A special thanks goes to Todd Pote for acting as a soundboard as I was planning the second part.
The session ended with a partial victory -- the party (members of the guard tasked with this investigation) lived where as other player characters ended up killed / murdered in the pursuit of other agendas. The villian of the story (my equivalent of the 'smoking man') got what he was seeking with the player characters none the wiser for it. One threat was eliminated but a crucial piece of the puzzle was snatched away.
The players has fun ... the were able to excercise their roleplaying talents and I was able to share my story where they did not feel constricted in what they could or couldn't do and where they could go.
Now that I've been able to give myself a bit of creative fun -- I need to get back to work.