Sun City has 130+ chartered clubs and a calendar of community events that would exhaust someone half the age of most residents. The official RCSC calendar lives at suncityaz.org; we're building a curated overview here with the can't-miss events and how to plug in if you're new.
Sun City Founders Day (early January, anniversary celebration), Sun Bowl concert series (Oct-April), Spring Fling (March arts & crafts festival), RCSC Annual Membership Meeting (where you can actually vote on community policy), and the quarterly New Resident Orientation at Bell Rec Center.
(1) Pick up the RCSC quarterly amenity guide at any rec center. (2) Attend a New Resident Orientation — they run quarterly. (3) Walk into any rec center and ask a desk clerk about the clubs — they'll hand you a list. (4) Show up at one club meeting; you'll be invited to 3 more by the end of it. The community is famously friendly to newcomers.