Monday evening is often a very busy time for people, and is probably often
very difficult to make. (I know it definitely will be for me for the next
several months, unfortunately.)
Perhaps we could organize a meetup on a weekend? I know a lot of other
places do this (notably New York) and it seems to work quite well, drawing
in people from outside of the city who could otherwise not make it so late
on a worknight.
Bhushan