We all know that alcohol/beer is very expensive in Singapore.
Some bars are offering +1 drink during happy hours but there are some establishments who surprisingly offers drink all you can!
Insomnia offers drink all you can every Wednesday, 9-11pm for Males and 9-12 for Females.
They also have a live band performing during this time.
Insomnia is crowded during these hours but since its drink all you can I think the crowd is reasonable!