I don't think I can explain it too well, but maybe you have heard of "Up Jenkins" which is a game that involves one side of the table passing a small object like a quarter under the table. They pass it until the other side calls Up Jenkins. Then they all raise up both hands (close fisted) and elbows on the table. The other side then says Down Jenkins and all bring their hands down flat on the table. The person with the quarter conceals it (tries anyway) and the other side gets three guesses who has it. It's kind of a kiddie game.
Maybe you could play What's my line?" with each side being a team. Everyone writes down a little known / unknown fact about themselves and trades in the group. Then group members read and hold up the paper. Each person claims that the mismatched fact is true about himself. The other team must try to get the right facts back matched with the person who wrote them.

I would think some paper and pencil games might work out the best. You could make up a crossword or word search using family member names, places the birthday folks have lived, things that are important to them, etc. You might be able to do up a bingo game, either normal bingo or some kind of birthday bingo.

You will be sitting at a very long table. That is a difficult stituation to engage everyone.

I have used the "POINTS GAME" for large crowds. You simply give everyone a paper & pen-and if they have what you call for-they give themselves the amount of points you assign to each-most points & least points wins a prize. Some examples are:
*10 pts for every photo yyou have of your spouse in your wallet
* 20 pts if you have a cloth hankie with you
* 5pts for each button yyou're wearing

Have a Bonus one at the end..like 50 pts for anyone who has a birthday in the month of the guests of honor's birthday, or for anyone who is wearing a certain color-

Hi -- Have a wonderful party! 80 and 65 - wow that's fantastic. We've had several parties like yours in restaurants - all seated at a long table. Don't be surprised if you talk all night and never get to a game, especially if any out of town visitors are there. It aways seemed that the time flew by and there was still more to chat about. Have a great time! -- :0)

Quick tip for situations like this.

Pictionary! You can do it with our without the actual store bought game. Simply make up cards with some things to draw on them. They either buy some marking pens and a paper flip chart or a message board and erasables from a store.

It's easy and cheap and in the dozen or so times we've done it, it's always been great. One of the best things about it is you can really effect the "mood" of the game by what you put as your drawing clues. You can do them so that even kids can get them, family oriented ones, sexy ones for an adult get together, etc. For yours, maybe you want to do all words that have to do with people in the room...cities they live in, occupations they've had, etc. and explain to everyone that you're playing Pictionary, The Jones Family Edition (substitute family name).

aiki

I think you do personal trivia. Ask questions about how they met their spouse, first car, first job, how many times they've moved, etc etc. The guests should wright down the answers who ever gets the most right wins, and the guests of honor get to tell stories about themselves and have a day that focuses on them.