Is a dinner party gift muktza? I've been invited to a Shabbos dinner and I would like to give the hostess a gift. I will be carrying the gift within an eiruv.
Let's assume we're not dealing with wrapping paper. (E.g. put it in a nice gift bag instead.) And other muktza-type issues have been addressed (there was the non-Jewish guest who brought cut flowers, and the hostess asked her nicely to set them down on the countertop as you can't put them in water on shabbos!)
Similarly, if the gift was outside the inhabited city limits at sunset on Friday and then somehow you sped on the highway there in time for dinner, that could be muktzah as well; I don't think that's your case.
The issue here is that the rabbinic ban on "business dealings" on Shabbos includes buy/sell transactions; this can make gifts tricky as well.
If you can't drop it off ahead of shabbos, your best bet (and I've seen this employed several times) is to make it that halachically belong to the hostess before you even arrive. Find some other Jewish person before Shabbos and say -- "would you please pick this up with intention to acquire it on behalf of Mrs. Hostess?" (Mrs. Hostess doesn't need to be informed of this; we assume people passively are okay acquiring things unless we're told otherwise.) Then you're all set.
If you are given any trouble, explain that you are not giving the gift, but retaining ownership of it and are allowing the hostess to use it in perpetuity.