Conditions of participation : 1. Participants have not been travelling outside Hong Kong the past 6 months. 2. Participants have not been in contact with Covid-19 patients in the past 6 months. 3. Priority is given to participants with proof of vaccination (first jab is sufficient). 4. Priority is given to participants showing negative Covid-19 test result within the last 30 days. 5. Participants must wear a mask throughout the evening. 6. Participants must observe the distancing guideline throughout the evening.