In comparison to San Francisco, LA, and San Diego (which collectively draw in a large percentage of the student population), San Luis Obispo's nightlife is a bit quieter. Few places are open around the clock, and not many more are open past 10 p.m. Most of the bars are restaurants by day, so they close after dinner to convert into San Luis Obispo's social scene for the 21-and-up crowd. Not 21? There are lots of activities sponsored by ASI (student government), University Housing, and different clubs on campus. Thursday nights are filled with two back-to-back, fun activities: farmers' market and line dancing. Both draw enough people to pack the venues each week, and everyone is sure to run into at least half of the people they know at either event. If this isn't your scene, then the Madonna Inn hosts somewhat classier nights with ballroom dancing.
Generally, Cal Poly students have a diverse range of interests. Outdoor activities are popular, so you can go rock climbing, play miniature golf, or go to the drive-in. There are a few cute coffee shops, which boast open mic nights and concerts. Linnaea's and Kreuzberg cafés are two of the more popular ones downtown. As far as the party scene goes, it's there as much as you look for it. It's easy to find and easy to avoid. You don't have to look far for a party if you know someone who knows someone.