The few times we have done this most times it turns into a weekend party and sleepover. This most times also requires the kids out of the house, we might be old (older) but we still get rowdy sometimes.
We have a few brewouts at our LHBS for Big Brew, Learn to Homebrew Day, Pearl Harbor Day, and Spring Brew. One of our members has a brewout on January 1st called the Recovery Brewout and were getting together on the 25th of this month to brew at a new member's home (with a pool). Our club also encourages Buddy Brews when a person wants to brew, they can send out a club-wide email to invite people to learn, help, brew, or just kibitz.