I'd really recommend talking to the organizers. And possibly watching one of their normal events. Here's some of my thoughts on potential biggies: -Many people will likely keep the same partner throughout the evening. -The expected flow of the evening is very different -- typically they're used to doing two dances with the same partner of about 6-10 (?) minutes, and then a rest break. Potentially involving snacks. Rinse and repeat. -Swings are neither expected nor required. Without further instruction, they'll go just once around, twirl, and stop. -Be very careful about too much consecutive clockwise motion. -You may have to adjust for the age level of the group. In general, MWSD groups tend to be older. -They're really not used to hearing the phrase of the music. -Dropping out the calls may be traumatic for some. -Contra is much more aerobic than squares.