Together with my colleague Enric Marco, from 2002 we conduct continuously open house sessions named “Friday Nights, Star Nights”. These sessions are carried out two Fridays per month from January until June. During these 2-to-3-hour lasting sessions we attend reduced groups (15-20 people) and explain them basic concepts of astronomy, cosmology and telescope operation. The session concludes with a telescopic observation of the objects visible at the moment.
You can find more information in the web of this activity.