I show up for the Tuesday night rides almost every week and they're a great workout.
We get about 30-40 riders and start from the top of the circuit (just past the right turn from JFK to Crossover) at 6PM sharp. 1st lap is a warm-up , then it's on. Some times guys try to break away for fun, but the real competition is for the stop sign line at the top of JFK each lap. We usually do about 6-7 laps (45-50 minutes).
These were my first "organized" group rides I ever did when I started about 2 years ago before I started real racing. At first it was tough for me to hang on the back, but I don't have any problems now.
Just guessing I would say that out of the 40 riders who show up we get about 5-8 Cat 2 (I don't know if any are Cat 1), about 10 Cat 3, 15 Cat 4 and the rest Cat 5 or guys who don't race.
A lot of the guys who get dropped sit out a lap then jump back in. Because it's just a workout no one really cares, though I did put up a $1 Prime for the final lap this week.
If you make it next week, come by and say hi. I'll be the guy in the ZteaM kit and matching Ridley bike.