There can be upwards of 140 youth at a conference. Cons are held at district churches. Other cons are run and hosted by individual youth groups. Worship activities can differ a lot from con to con, and can be anything from a water ceremony to finger painting. Workshops take place in the morning and afternoon on Saturday and can also vary a lot, from cookie baking to creative writing to massage to cross dressing to ultimate frisbee to watching and discussing a movie.
Family groups are small, random groups of people.
When you get to the con, the registrar has put you in a family group. Normally you have a family group leader who is on DYSC if it is a DYSC- run con or is in the host youth group. The purpose of a family group is to get to know people and to have a place to touch base every once in a while since conferences are often very large. Your family group is put in charge of either preparing or cleaning up after a meal, so the work is divided somewhat evenly among conferees. Your family group is also your team if the Saturday night activity is a game that requires teams.