Kiddush in shul this morning was given in honor of Shushan Purim Katan, which I thought was interesting because I never knew there was such a thing as Shushan Purim Katan. I told me wife afterwards that I guess it really doesn't matter, because, as the Rama says, "Tov lev mishteh tamid," so what's one more day of partying.
Truth be told, the Rama may actually address this issue. Rama (O.C. 697:1) writes, "Yesh omrim she'chayav l'harbos b'mishteh v'simcha b'14 Adar Rishon..." Notice that the Rama says nothing about making a party on 15 Adar Rishon -- he only mentions 14 Adar. And remember the gemara (Meg 6b) that we quoted last week -- "There is no difference between 14 Adar Rishon and 14 Adar Sheni except for reading of megillah and matanos l'evyonim" -- no mention again of 15 Adar. Of course you could argue that the gemara, and perhaps the Rama, are speaking in a general sense, as most people observe Purim on 14 Adar. However, the Pri Megadim for one is convinced that the diyuk of 14 to the exclusion of 15 is correct, and the Mishna Berura follows suit -- there is no chiyuv to make a party on Shushan Purim Katan. (Since 15 Adar was on Shabbos this year things may be a little different, as, at least according to the Yerushalmi, even if Purim itself fell on Shabbos the din of having a party is pushed off to another day. ) Shu"T Minchas Yitzchak (vol 10 #58) is less convinced, and he cites a Levush that argues in favor of celebrating both days.
The Minchas Yitzchak quotes an interesting Ksav Sofer (found in his commentary to Parshas Titzaveh) who suggests that since the whole point of mishloach manos is to contribute to and share in each others seudos Purim (the Briskers read the Rambam this way if I am not mistaken; others suggest that mishloach manos is just to enhance re'yus, the bonds of friendship between neighbors), there should be a din of mishloach manos on Purim Katan just like Purim in keeping with the Rama's psak to have a seudah in celebration of Purim Katan. Since no one delivered any mishloach manos to me before Shabbos, and I did not see anyone else out delivering to others, I am pretty confident this minhag has not taken off (unless, like the superbowl party, it's just me?)
So how do you decide between a diyuk of the Pri Megadim and a Minchas Yitzchak? Doesn't the Rama answer this one already? -- "Tov lev mishteh tamid!" which brings me right back to where I started.