No, we're not really having a party. Not anytime soon, anyway. But I got your attention, right?
I promised a post on using both the plural and the possessive with surnames. And you've waited with bated breath. So here it is. Now, why does the title of this post have s' at the end?
First of all, it's plural. Hence the "s." There are three of us Conklins (four if you include the dog). One Conklin; four Conklins. (Please see my previous post for more on this.)
Second, it's possessive. Hence the apostrophe. "How is it possessive?" you might ask. "There's nothing after Conklins' to show what they possess." True. But what is implied is that the party is at the Conklins' house, which they in fact possess (or possess in part, anyway -- the bank that owns the majority of it rarely holds parties there. Having too much fun crunching numbers, I guess. Or counting their (our) money.).
So, are we clear? The only time you need an apostrophe with your surname is to show possession, as above. Although, come to think of it, you could also use an apostrophe to make a surname a contraction: That Conklin's a genius. In which case the apostrophe comes before the "s" because you're talking about only one of the Conklins (the dog, of course). Let's just not use that one too often, OK?