Dates. I believe most dates go well unless they're not planned and you end up at an Applebee's. And I'm not THAT opposed to Applebee's if you don't act all: "Well that's weird they lost my reservation for this four star restaurant, but I know there's an Applebee's up the street." (Ok, guy.)
But I mean, if you're into other things, like cutesier things, May is the perfect time for picnics.