|Your keynote speaker|
Ok, one thing that gets discussed in most superhero game books but is chronically hard to actually wedge into a game is subplots.
Modules generally have villains and scenarios laid out, but the part of the comic where not only does the Flash have to stop the Meteor Men from eating Atlantis but has to rent a tuxedo for his cousin Alf's wedding is not usually written into the game and it's hard to design since--unlike a villain--it has to be individualized to the character and it isn't necessarily easy to play it out since the player doesn't have a clear goal--which can leave the other players going "Ok, how long are you pretending to talk to your landlord before we can go back to the game?"
On the other hand, without these, you lose a dimension of the game--even in a tactical sense. The Kingpin's awesome plan in Born Again wouldn't work if Daredevil didn't have a connection to Karen, Foggy, Ben, et al.
Jeff Grubb solved this problem. Here's how:
Making a commitment gets you karma--which is a spendable experience point thing you can use to beat people up or not die or whatever. If you fail your commitment you lose it.
That's it. That's the whole mechanic and it works like a charm. Players invent subplots for themselves and interact with unsuper NPCs all the time.
The genius of it is: it's the only Karma award a player can just get without doing anything hard. So the player is not only incentivized to build out his/her PC's private world, it's the only thing on the table they can be sure they'll be rewarded for--no risk, no waiting for villains to attack, etc. the PC doesn't even have to leave the house to make a commitment.
Example--the players are hunting for Nazi science jerk Arnim Zola:
"Ok I'm a chemist would I know Arnim Zola?"
"Funny you should mention that he spoke at your school a few months ago."
"Can I talk to whoever coordinates the visiting lectures?"
"Sure it's a fellow student" (idk, that's how it worked in art school)
"Ok, I'll call them"
"'Hello, Gwen Stacy speaking?'"
"'Oh it's you--omg, giggle...'"
"Oh god I don't want to go out with her I know she's gonna die"
"There's karma in it..."
And then Sleepless the paranoid numbercrunching social leper goes on a date with Gwen Stacy while everyone else is watching the Vault for boats full of supersedatives and I get to attack the movie theater with Ani-Men. And then Sleepless has to pretend to spill popcorn on Gwen so that he can get away to the lobby and fight them. Classic.
Incidentally, this belies the old saw that a game is 'about' what most of its rules are about--this 8-word rule creates immensely complicated situations.
I feel like other games could use a mechanic like this--not every genre, but any one where you want a semi-static social constellation (as opposed to exploration or fast-pitched thriller pacing) to be a part of the game. Like RIFTS+ this mechanic basically gives you Apoc World on the cheap.