For me it'd be:

May 1st- Turkey opener. Nothing like getting back out in the woods in the spring. Smelling that fresh air, hearing all the wildlife coming alive at dawn after a long winter.
Sept.27th- First time out bowhunting of the yr. Nothing like climbing up into that stand for the first time!!

If your talking about dates of regular success, I don't really have any, it can happen for me at anytime while hunting. But around 11/7 -11/12 seems to be the dates the rut kicks in good down to my camp in Cortland Co. year in & year out.