What recurring, low-pressure activities on a budget engage condo residents?

[JonathanW]

I'm on the social committee for my condo building, and we're trying to move beyond the usual holiday potluck to foster more regular interaction and a sense of community among residents, many of whom are young professionals who keep to themselves. We have a modest budget and a common room we can use, but our past events have had very low turnout, and we're struggling to come up with fresh community engagement ideas that would appeal to a diverse mix of ages and schedules. For others who have successfully built connections in similar residential settings, what types of recurring, low-pressure activities actually got people to come out? Did you find success with skill-sharing workshops, casual game nights, or interest-based clubs, and what were the most effective ways to publicize events and gather feedback without becoming a nuisance in everyone's mailbox or online group?