Surprise wedding

Me and my fiancé have been engaged for over 2 years now. We were meant to be getting married in January but it didn't happen so we are thinking about doing a surprise wedding. We are thinking about getting everyone together for some kind of party and then announcing that it is actually a wedding when all our close friends and family are together. Anyone have any ideas on what reason we can get everyone together? Was thinking a belated engagement party but it's very late for that that haha. We want to have it during the spring or summer time.