While we are all experts in experiencing time, introspection often provides us with very little intuitions regarding the neural mechanisms underlying how we perceive time. Over the last decades, research in cognitive neurosciences has shown that different parts of our brain and different neural mechanisms contribute to various mental representations for time perception and cognition. In this talk, I will discuss the idea that be conscious of time is to render intelligible the non-stationarities of brain activity. I will argue that clocking mechanisms (e.g. measured as neural oscillations) are foundational to comprehend the biology of the mind by reframing temporalities from the perspective of the brain itself (as generator-observer) as opposed to that of the external observer only. These notions will be illustrated with empirical work using psychophysics and functional neuroimaging (MEG, fMRI), ranging from low-level simultaneity and order perception to mental time travel.