Iwasblind - if you aren't ready to tell them you didn't go to one of their "ignore fests" just say "Oh we had a change and went to a different Memorial this year, why do you ask?"
They will say "Oh I didn't see you at ours and wondered where you were?"
You "Yes we went elsewhere, thanks."
Them "Oh, where?"
You "Elsewhere." (Shrug) - repeat until they get the message you aren't saying any more.