I think the Winter Classic on New Year's Day still draws, I'll watch it every year if I'm home. I've always wanted to go to 1.

The Stadium Series has diluted the excitement a bit but I went and it was a really enjoyable atmosphere (aside from the wind and Isles fans). Diluted or not, Metlife Stadium saw like 150K-ish people over the weekend.

The Heritage Classic in Canada I have no idea but I imagine it sells out every year and will continue to forever and ever.