Here is a challenge I have created myself with the goal of making it through all the expansion packs. Each generation has a goal based around an expansion pack. Below are the rules as well as how to get started.

Create a young adult sim male or female. This will be your founder. You may give them any trait you wish. Their lifetime goal is also up to you but keep in mind they can never hold a job. Move them onto any size lot however I suggest a medium sized lot because they will be moving to a new neighborhood eventually. Give them a sleeping bag (Generations Needed) then set their family funds to 0.

#1 -Each generation must complete their goal before the next heir can start theirs. The more time it takes you the less tiem the next generation has. A Sim must complete their goal before reaching elder, and may not start before they are young adult.
#2 - Once an heir has been chosen all other sibling must move out upon ageing to young adult. Also one the previous generation had completed their goal they must move out. The exception is the founder who may continue living in the house until they pass away. Their spouse however must move once the goal is complete.
#3 - For generations 6, 7, and 9 the sim must move to the appropriate towns. 6 - Starlight shores, 7 - Isla Paradisio, 8 - Midnight Falls.
#4 - Remember this is one family you are playing. The object is to reach 11 generations each one completing their goal.
#5 - All children must be involved with the maximum number of after school activities they can. I believe it is 2. Teens must also take drivers ed. Each child you have must also be on honor roll.

Generation #1 - The Founder -
The founding generation's goal is to earn 100,000 simoleans without ever holding a job. You must keep track of how much they earn because no other sim's earned money may count towards their goal. You may not register as self-employed. (Ambitions Requiered)

Generation #2 University
This generation must complete 1 university major, as well as reach the max leverl in two social groups.

Generation #3 World Adventures
You must travel the world visiting Al Simhara, Champs Les Sims, and Shang Simla. You must complete 1 world adventures lifetime wish. (Bottomless Nectar Cellar, Private Museum, seasoned Travler, or World Class Gallery.)

Generation #4 - Ambitions
You must have your heir reach the top of one ambitions profession. (Architecht, ghost hunter, inventor, private investigator, sculptor, or stylist)

Generation # 5 - Pets -
Complete one lifetime wish from pets (Animal Rescuer, Ark Builder, Canine Companion, Cat Header, Culinary Helper, Fairytale Finder, Jockey, or Zoologist)

Generation #6 - Showtime -
Move your heir to Starlight Shores. Have them reach level ten in the singer, magician, or acrobat career track.

Generation #7 - Island Paradise -
Move your sim to Isla Paradisio . Have them own a five star resort, and meet mermaids.

Generation #8 - Seasons -
Move your sim to Midnight Falls, Have them experience all found seasons. They must get a photo at each seasons festival and complete the perfect garden lifetime wish.

Generation # - 9 - Supernatural -
Your heir must marry a sim of a supernatural race (Werewolf, witch, vampire, or fairy. Then have their spouse complete the appropriate lifetime wish. 9Werewolf - leader of the pack, Witch - Mystic healer or Zombie master, Vamp - Turn Town, Fairy - Greener Garden) Your Heir (Non Magic Race) must complete one lifetime wish not associated with the magic race. (Alchemy artisan, celebrity psychic, master of mysticism)

Generation #10 - Late Night -
Have your heir complete both film career and master romancer lifetime wish.

Generation #11 - Into The future -
Travel into the future. Each of the following must be completed to complete the challenge. Cheat to win the lottery twice. Experience all three possible futures, have both your spouse and you heir get a legacy statue.

That's the Generations Legacy Challenge. I will edit this I I see their is a need to. If you see something that needs changed, or you think the goal for each generation needs to be in a different order let me know. Happy Simming.

Also to check out the Challenge in action you can view me playing it for the first time ever here.
Thanks To the following people for giving their input. If you play the challenge and find something is to difficult or something else that works better please let me know. And feel free to play this challenge as you wish. The more people that try different things with the challenge and give feedback the better the challenge will become.

ladykelien (for pointing out that I had the tasks ordered wrong, and that 200,000 might be to much to reach)
playeroflif3 (For letting me know that the sleeping bag and self-employment were with ep's)

You might want to rethink this a little. If your going by expansion packs you have them in the wrong order. Plus, it seems rather impossible to me to earn 200,000 From Painting, Writing, Gardening and Fishing without cheating. EP order is as follows:

Base Game
World Adventures
Ambitions:
Late Night
Generations
Pets
Showtime
Supernatural
Seasons
University
Island Paradise
Into the future

I didn't see anything in the different levels that might require use of something from an EP that had yet to be released but you might want to check around to make sure you have covered all of your bases

Thank you I have made some changes and will fixe it on here as soon as I get the chance. I have reordered the tasks by the order the ep's came out and changed the 200,000 simoleons to 100,000 simoleons. I am currently testing it out in game to see if either is possible.

Just mentioning that you need Generations installed to get a sleeping bag, and you need Ambitions and not a mod for self-employed careers.
A lifetime royalties mod might be useful for getting the 100,000 or 200,000 simoleons needed for the first generation. Would I be allowed to play with that?

You're free to play the challenge how you want, but the point is to complete all the tasks without using any kind of cheat or mod. If the money is to high that cn be adjusted. I am currently playing through to see if it is possible.