Ashtanga yoga mysore classes. Everyday from monday to friday, (except full or new moon), the CDO opens its doors by the hands of Tiago Doria, to welcome students of any level or new students, and also drop ins for 10 euros per class. Its mysore style, so you can take your time and garanteed atention from the teacher, who is one of the most patient persons I've ever met.
The palace is a good place to practice, either you are beginning, advanced or just visiting Portugal.
You can get there easily by train to Algés (Estoril line), or tram nr 15.
Tiago has recently come back from a 3 month stay at Ashtang Yoga Research Institute where he was studying under Sharath Jois, and teaches regularly in Northern Spain too.
Good place, good teacher, a must do.