Oeiras has a free music festival every year. The 2025 edition started May 30th, and will last until June 15th. There are also mini-concerts for kids, taking place during the weekends. Most shows happen in Jardim Municipal de Oeiras, and a few at Parque Urbano de Miraflores. https://lisboasecreta.co/en/oeiras-festivities-2025/
There are also restaurants and food stands available.😋