The total entropy of an isolated system, such as the universe, can never decrease over time. This has some unfortunate consequences. For example, cleaning my room will decrease the level of disorder locally, but only by producing large amounts of waste heat that will increase the overall level of entropy (unavailable thermodynamic energy) in the universe.
Therefore, I have decided to help keep entropy at bay by sitting around today and doing nothing at all.
By my calculations, I have prolonged the life of the universe by approximately one googolth of a second.
PS: I thought this was my own idea, but here’s a good article exploring it in more depth.