lots of interesting stuff, campaign failed due to sandbox.
Thats interesting to me because I dont think I've ever had a campaign fail due to that and I almost never have a main plot in the first place.
In my current game for instance the players are part of a mercenary group that post-war of the ring (slightly altered ending) in middle earth decided as a group that they were going to take over a city in the mountains based off of the pirate city of tortuga, except to the 9th degree.
Now if theres a main plot its this extended group defeating the other gangs to control more and more territory until the city is theirs. They havent done much of this.
The groups main enemies at the moment are a gang of orcs who wandered down from Angmar. They've fought them once and it turned into a retreat....
The last 3 or 4 sessions have been spent doing various jobs for the people in their territory because some of them want to be a good gang. So they've been gathering funds to build a hospital and set up an ambulance service, investigating missing patrons in their (biggest bar/brothel which is turning out to be a vampire guild at work) and most recently in the midst of that investigation getting sidetracked after learning of an unsolved murder from a ghost 2 of them decided to punish the murderer since he was in the same tenement. So they made him confess and turned him over to an evil spirit of despair who ate him. Then they spent about an hour figuring out the best way to take over his string of marketplace vegetable stalls and interviewing a manager to run it for them.
Now I didnt see any of this crazyness coming. I put together an adventure involving getting the allegience of the local temple of goodishness but 2 players had to work overtime the day we were gonna play it so I threw together the solve the bar patron murder on the spot to kill a little time and then when they seemed more into what was happening then in talking to priests I just kept the mystery going deeper and deeper while they explored their gangs territory and the city looking for clues.
Its been a great couple of weeks of gaming for all. My campaign plan is absolutely off the plan, not even close at this point actually so maybe by some definitions its "failed". But I think its been one of the more interesting campaigns i've been in for years. And everyone keeps showing up on time and emailing me questions and ideas throughout the week between games so they're engaged and we're all having fun even if we've spent an absurd percentage of time doing things that arent traditionally "adventure" and to me thats a success.