There doesn't need to be a specific reason for a reunion, it could be something planned for ages like a wedding, baptism, birthday, or yearly reunion.  It could also be that everyone decided a week before to get together.  Whatever the reason, when hoards of extended family members are together it is a primo time to record those memories.  This is especially important if you have globe-trotting family members.  In my family, we get all-together about once in every five years.  I live six hours from the homestead and my brother needs to add another twelve hours onto that drive.   As my cousins are growing older, they start traveling to far off colleges and more.   I'm sure family situations can greatly differ but it always seems difficult to get everyone together in one place at one time.  Even a one hour drive can sometimes be hard to schedule. So if a get-together happens, I call it memory gold.  It is also a great time to plan on getting individual family images or creating your holiday card.  
 

Here are a few tricks and tips for getting the best images from your extended family session.

1.  Hold the littlest ones.

 If you are a parent of a little one, plan on holding them.  Even if you are on one knee, holding your little one will keep them in the picture and you can be there to direct them where to look.  No one likes chasing little Johnny around the group while everyone else is waiting to give their best smile.  Holding is a great alternative!

2. Try to wear simliar colors for each family, or have everyone dress in a similar fashion.  

I love individuality.  I even suggest dressing vastly different from others in some group portraits.  In major family images, it is easier to focus on each person's face when your clothing blends together, either by color choice or pattern. This is not a must, but a little trick for more concise images.  

3.  Plan on taking images in the morning or evening.  Avoid the heavy sunlit hours.

 If the morning or evening hours aren't available, I suggest having a predetermined location with a lot of shade for your image.  Having harsh mid-day sunlight can create malicious shadows on faces, covering eyes and more.  If you can find a large tree or other covering for your images, the photographer can use additional lighting or adjust for the shade in their camera.