In college, a friend and I analysed sleep using EEG data to understand how brain activity changes overnight. We used signal processing techniques, like the multi-taper spectrum, to clean the data and visualise shifts between different sleep stages. Our analysis matched what the literature says: sleep follows a predictable pattern, from light stages to deep sleep and REM. We found that dominant brainwave frequencies corresponded well with each stage, and our plots (hypnograms and power spectra) showed regular, healthy sleep cycles. It was a great introduction to how neuroscience and computation can come together to decode the rhythms of the sleeping brain.