At first glance our understanding of the universe seems to be solely anchored in classical gravity. Indeed, General Relativity (GR) is a powerful tool that provides a successful geometric description of the cosmos. However, if one scratches beneath the surface, the universe becomes a fascinating playground for thermal and quantum phenomena.

In this talk I will present recent developments in both avenues. First, I will present the covariant formulation of non-equilibrium thermodynamics in GR, which is a consistent synthesis of the laws of thermodynamics and the variational formulation of gravity. The General Relativistic Entropic Acceleration (GREA) model is built upon this framework and proposed as an alternative to the cosmological constant to explain the current accelerated expansion of the universe. Second, I will discuss ongoing work on the possibility of performing cosmological Bell experiments in real space to test the quantum origin of primordial perturbations.