Upvote:2
Well, if you are a layman looking for free food, come to Sri Lanka during the Vesak or Poson full moon poya days. You will find many free food outlets. Usually you can get rice & curry, noodles, sandwiches, ice cream, various beverages etc.
If you are a monk, you can go on alms round on any day. You will be offered food in most cities.
If you're actually looking to do the dana offering to monks, just go to any temple and make your wishes known to the head monk: they will give you a date. Alternately, you can go near monasteries like Meethirigala and try to catch a monk who's going on alms round. Here's a recording I did in January: Pindapathe on Election Day