The annual Rose Festival takes place each May over a long weekend timed to coincide with the rose harvest. It is a genuine community event rather than a tourist production: there is a rose queen election, a parade through the town with floats covered in petals, music from regional groups, and stalls selling rose water, rose jam, rose oil, and every conceivable rose-derived product.
The festival draws large crowds from across Morocco and has become increasingly popular with European visitors, though it remains much less commercialised than similar events in better-known destinations. If you can time a visit to May, it is worth arranging your itinerary around it. The exact weekend changes year to year, so check before booking.