I am totally out of it. I said some things to my therapist that sent my
   psychosis into convulsions. I can barely consider goals.
   I found a nice one: I spend so much time without good motor control,
   painfully associated with my goals and values, that I have a lot of
   experience daydreaming around pointless stuff to pass the time. One
   cool pointless project is the idea of a time travel video game. I've
   started it a few times, hard to get anywhere with though.
   Current behavior may be changed to boss story activity or something
   productive.
   The current attempt to draft this video game design is
   at [1]https://github.com/xloem/multiplayertimetravel . The repo is
   basically empty.
   The idea is to get multiple players into an experience where they can
   time travel and interact with each other in each others' past and
   future using techniques such as simulation, prediction, vagueness,
   multiple timelines, etc. It's interesting because it sounds impossible
   when you propose it but is not too complicated to fake.

References

   1. https://github.com/xloem/multiplayertimetravel