Swing dancing -- "switch dancing"

Something new happened at last night's Friday night swing dance which I will call a "switch dance" but I'm sure there is another name. We were all on the dance floor watching the jam session and once it was over the dance started up again but with a twist about every 15 seconds we had to change dance partner. The DJ would call out "change" and we would dance with the closest follower. Over about a four minute period I danced with a fair number of women and many of which, I have never dance with before. It was a great way to meet a lot of dancers in a short period of time. After the dance I was able to dance with some new women which was great.