We've tried a few times, just for the people who live within a couple of hours of here. No matter who hosts it or how it's organized, it seems to be an expensive project.

This article from Dollar Stretcher: Handling an Overpriced Family Reunion has some good ideas that I've been kicking around. Do you have anything to add to it? 

My husband has a large family but we do try to gather together at least one a year and include as many siblings/spouses, children and grandchildren (40-60 people). We're spread out all over New York state but we usually end up in the Northern Tier in the Adironacks where my in-laws live. Its usually a Lebanese meal supplemented with other salads and side dishes. A couple is SIL's usually coordinate and tell us what to bring. The food situation works out great. The sleeping arrangements have gotten more complicated since there are more young ones (under 10) and some families travel great distances. Since DH and I are 2.5 hours away, we opt to come home and sleep in our own bed. The only issue is that many family members own dogs and often bring them to these gatherings. There have been as many as 7 dogs and they get a "pack mentality" if they aren't supervised or restrained. That has been the only issue. The expenses go for whatever food is made and gas to get there and back.

 Not usually but since my Dad got ill last year, we all got together in September for the first time in 28 years.  Then on Father's Day we are having the memorial service for Dad who died on Mother's Day as that weekend my brother flies in from the UK again.  He had it planned before Dad's death and could not change or cancel it without penalty.  So we all decided instead of no service to have a celebration of Dad's life.  Luckily my younger sister can put me up and my brother and sister in law.  2 Step brothers and their families live in Calgary and the other Step Brother is coming from Sask. and staying at one of his brothers' house.  There is a hall booked which is providing lunch and my Step Mum is funding the whole thing.  I just have to get there which will be by maxi scooter and should cost me under $100 for the ferry and the gas.  I should be able to do it in  1 day.

Hugs Sally.