So here is the original creator of this challenge http://modthesims.info/showthread.php?t=556386
Backstory
as a kid you dreamed about helping animals find a safe home! so now that you've moved out you have purchased a plot of land and are ready to bring your dream into a reality!
Explanation
so this is my version of it it's a bit different and has some more scoring and stages but if you don't like something feel free to change it!
Setup
you will need to create a sim girl or boy no matter you can choose whatever trait and LTW you want, however the focus is not on the LTW it's on the rescue center.
if you want you can start with 2 pets but they may NOT be horses. (see Events) however if you start with pets they do not count as strays that you found so you do not get points. they can still be adopted but no points received for them.
after you have your household pick an empty lot it can be any size then using cheats set family funds to 20,000 by pressing CTR SHIFT C at the same time and then typing Familyfunds <household name> 20000. you can then build your rescue center which moves us to the next one
Requirements
you must have
1. your sims house it must have the necessities for living shower fridge bed ect.
2. each pet must have their own room with food a bed and anything else they need e.g cats-scratching post dog-dog house etc. (for the big dogs you may or may not be able to fit a bed so if you can't fit them just use the doghouse that will count as a bed.
3. you must have a place to bathe your pet (which is not YOUR bathtub.)
4. you need to have a yard however different animals MUST be kept separate. so make sure you split the yard and fence it off.
5. you will need an area for your animals to give birth and the kids and their moms will stay there until the kits/pups/foals become adults. (the dads can visit unless it's a pregnant stray;see events)
Events
at first you may only have cat and dog strays in your shelter do to the fact that you have just started and do not have the funds for a horse (pretend you don't) as you progress through the game you may unlock such things and more.
Day 5: you hear a lonely yowl outside your door and find a poor cat she is clearly pregnant do you take her in or not?
if you take the cat in you can either adopt a cat from shelter or create a cat and add it to the family. however you will need to use cheats to make that cat pregnant and the cat must be a female. if you don't take her in do nothing but your sim will not be able to sleep for 8 hours because of guilt.

Day 10: As you go to the grocery store to buy more food for your animals you see two boys chasing a dog down the alley. they then leave laughing. you go to look and see a sad dog who is hurt at the dead end of the alley. do you take it in and nurse it back to health? or do you leave it behind?
if you take it in same process as the pregnant cat except you don't make the dog pregnant also the dog can be any gender. however you must bring their hunger down to almost starving and then must stay/play with it for 1-2 hours (by doing this you are nursing it back to full health)
When you raise 10,000$ you unlock the horse meaning you can now buy a horse! however try to make it realistic so you have to have a barn and field for it as well as at least one jump, or race track, or both.
Day 17:you win the lottery! add 2,000 to your household funds (just use ka-ching twice)
Day 20:If you helped the pregnant cat you receive 5,000 from the government for actually helping the animals (ka-ching 5 times!)
Day 26: (only do this if you didn't help the dog on day 10) you walk the dog through the park he starts barking but you ignore it when you get home you find 3,000 dollars missing (do some math and figure out how much needs to be taken away e.g if i had 7,500 i would set family funds to 4,500)

another thing that must be mentioned in events is that every Wednesday and Saturday your animals are up for adoption (if you want you can change the days but it has to be 2 days!) you can't actually put them up for adoption because then they get taken to a different animal shelter. just have 1-4 people come and decide which one gets to adopt a pet (use cheats to move them to that household or go to edit town)
if you have only 1 animal left in your shelter adopt more from other shelters or get strays. also once an animal in your shelter is adopted just add 1,000 to your household funds by using ka-ching

Rules
1. no money cheats unless you won it from the events or when someone adopts a pet otherwise stay away from money cheats you must earn your own money and use it for the shelter.
2. don't let your animals get taken away by social workers.
3. you should never have less then 1 animal in your shelter. however if you have found homes for all animals thats fine!

Goals
easy: have found homes homes for 10 animals!
Medium: have found homes for 15 animals!
Hard: have found homes for 20
Extremely hard: have found homes for ALL animals! (This includes stray's and wild horses also 2 unicrons)

Scoring System
+100 points for every stray you take in
+100 points for every animal you find a home for!
-100 for every animal that dies before it is adopted from your shelter
-200 for every animal taken away by social worker
you LOSE if you have no more animals left in your shelter UNLESS there are no more animals left and all of them have a home!

so yeah i hope you enjoy this challenge give me suggestions i will try to update it as often as i can! have great day/night/dawn/dusk/evening/midnight etc.