TU Darmstadt has many student clubs, for example movie circles or orchestras. You can also join one of the many sports teams (see Hochschulgruppen and Unisportzentrum for more information).
Darmstadt is a diverse city which has a lot to offer, for instance parks, green areas, the Vivarium, the Mathildenhöhe, museums, theatres, markets, sport events, restaurants and more.
With your student ID card you can visit the Staatstheater for free if there are tickets left three days before a performance. See Staatstheater Darmstadt for information about performances.
If you have already explored Darmstadt, you can also take the train to Frankfurt – this only takes about half an hour.