Whereas the general principles of dynamic cell cycle regulation are now well understood, we know much less about their coordination in space and with the organisation of the nucleus. In this talk, I will present two short stories of our latest results demonstrating cell cycle regulation of chromatin and its importance in cancer. The first is about a novel phosphorylation of histone H3 that we have discovered and its involvement in maintaining genome stability during DNA replication, and the second concerns the ubiquitous mammalian cell proliferation marker, Ki-67, that we have found links heterochromatin to the cell cycle and senescence.