Hug your children

A universe death clock, built in Minecraft

Some interpretations of cosmology and the laws of thermodynamics imply that eventually, the universe will freeze and die. If galaxies keep racing away from each other, stars keep burning up their nuclear fuel, and entropy keeps increasing, then eventually all matter, including black holes, will decay and the universe will asymptotically approach a temperature of absolute zero.

Some guy cooked up a mechanism in the video game Minecraft that will take a bit over 1 googol years to complete, which is about the time that it will take for all the black holes to evaporate via Hawking radiation. In case you aren't feeling nihilistic enough this morning, it's pretty great:

Note, however, that this isn't the only possibility for the ultimate fate of the universe. Far-future thinking like this can get extremely weird.