We all know working out with a group helps with accountability but I think the biggest benefit is a harder workout. More often than not when I ride/run/swim with others I go farther and/or faster than I otherwise would on my own. That means a group workout = more calories burned & fitness gained. I'll take that!
Below is a great cycling workout to do with a group of about 3-5 riders. The time will fly by as you catch up with your friends but you'll also get in a tough workout too!