i didn't read every response but these things erked me on the group ride i was in 2 nights ago:

- HOLD. YOUR. LINE. if there's a little bump/crack/hole then sure, move around it in a CONTROLLED fashion. but if you're in a 2 abreast pack that's going at a fairly aggressive pace and people are rotating out DO NOT swerve drastically to avoid tiny road imperfections!!!! there was a dude who did this to avoid what was just a ~8" wide hole that was only 1/2" deep! he nearly took out 10 people and pissed off the entire group. idiot.

- know when and where sprint points are if you plan on joining in on them. if you don't plan on participating then GTFO the way! stay to the rear. furthermore, if you'd like to participate but KNOW that you have no realistic chance of winning then stay to rear of the sprinting pack, HOLD YOUR LINE, and control your out of the saddle effort!