The cell is a complex autonomous machine taking in information, performing computations, and responding to the environment. Many of the internal structures and architecture is transient and created through active processes. Recent advances in active matter physics with biological elements are opening new insights into the physics behind how cellular organizations are generated, maintained, and destroyed. I will present several stories about how microtubules can be self-organized into cellular structures using molecular motors (kinesin-1), crosslinking proteins (MAP65), and the inherent microtubule polymerization. These works illustrate the importance of the fundamental physics to build the structures inside living cells while informing on new physics we can learn from biological elements and materials.