Possibly finding a way to transport themselves to another universe - another idea I heard was if there's a "Big Crunch" and if entities "uploaded" or transferred their intelligence to machines - a black hole whose matter was rearranged into a computer that continually became more compressed during the crunch, it would produce the sensation of infinite time.

I forget who came up with this but I heard one idea that black holes, at least some of them are actually superintelligences that communicate to each other using quantum tunneling, I think. The idea being that for computation, the smaller and denser the better - so at some previous point, intelligent entities uploaded themselves into rearranged black holes, leaving the universe.