Easter Eggs
Information about NPC's, and other secrets in the game.
*Warning* spoilers ahead, do not read if you want to discover these things for yourself
Not strictly an NPC as they are never seen. You might get abducted by aliens one night if you make a sim to look through the telescope at night. It's a random event but if it happens your sim will be abducted for a day or two and when they come back their personality points have changed. They also can't stop talking about aliens.
If you are the proud owner of the Unleashed expansion pack then you have a chance to spot the elusive loch ness monster right in the heart of your Sim's neighbourhood.
Leave the game on the neighbourhood screen for a few minutes and with a bit of luck you should see nessie swim by. This also works on the downtown and vacation island screens.
If you are impatient you can bring up the cheat screen while on the neighbourhood screen by pressing and holding Ctrl+Shift+C and the grey box will appear, then type "Nessie" without the quotes and you should see her swim by.
There are two versions of the credits:
Pictures of the crew are hidden in various places in the game.

I have all of the expansions up to HD so I don't know what combination of the others this works on but on the start up screen when you are given the options of what screen resolution you want to run the game on, in the lower left corner of the screen is the Maxis logo. Run your mouse over it and it will change into it's normal colours, then click on it to see a surprise picture.
The following is a list of some of the NPC's in the games with details on how to see them and which expansion pack is required to see them.
The burgular comes at night after your sims are all asleep. If you have an alarm installed near each of the entrances to the house it will go off alerting the police and if they catch him in time you will receive a reward and compensation for any items that he stole.
If you don't have the alarm installed you will find that it takes your sims too long to get up and phone the police themselves. He will be long gone by the time that they get there.
If you just have the original sim game then his appearance will be quite frequent until he gets caught, with the expansions however his appearance is rarer.
Make sure your Sims have a fireplace and the Christmas Tree and put out a plate of cookies. Get them all to bed early and at around midnight Santa Claus might drop in and leave some presents.
The Grim Reaper appears for two reasons:
No not a 70's pop group. If you hang the Sad Clown painting somewhere in your house and your sim's mood bar is right down in the minus values then the sad clown might come to your house. He just hangs around and makes you sims more miserable. To get rid of him you need to download the clowncatchers from "Get Cool Stuff" at thesims.ea.comYou just phone them and they come along a take him away for you.
Owners of the expansions after LL do not need the download as it is included in those game files.
The pink monkey appears when you hire the female entertainer and there is a child in the room.
The mime turns up at your party if one of the guests is having a really bad time and her mood is really low. He won't leave when asked and just annoys everyone. The only way to keep him at bay is to make sure everyone has plenty of things to do and they're not left on their own for too long.
If your party starts to get into the swing of things then you may get a visit from the Dropinski's These's are the gatecrashers. They are a bit messy and tend to use your stuff but it does means that your party is starting to hot up. Keep it up and Drew Carey might turn up. He turns up in his limo and everyone runs to see him. He then mingles with your guests while you can bask in the glory of hosting one fab party.
There are two ways to see the ghosts:
This character can sometimes be found rummaging through your trashcan looking for something to eat. Some people have also sighted her downtown going through their picnic baskets.
If you own MM put the honey making workshop somewhere in the garden and make some honey and leave it out there and Claire may come along to try and have a bit for herself. She's harmless and for some people a rarely seen NPC.
This guitar playing minstrel can be found Downtown in restaurants that don't have a piano in them. You can request a song or tip the minstrel so that he will play a song for your date. If you tip him enough times he'll play the violin instead.
The Prude or Mrs Crumblebottom to give her proper name is the widow of Mr Crumplebottom. She spends her time wandering the streets of downtown, complaining about the dirt and if your sim should dare to show affection towards another sim while she is watching she will come up them and tell them to leave it to somewhere more private. She might even hit you with her handbag if your 'crime' is severe enough.
When your Sims go to vacation island they may see one of these guys. They hang around waiting till one of your Sims is left just standing there and then they'll come up and give them a hug to cheer them up.
You could see Betty the Yeti in the snowy locations, Marky the Sharky on the Beach and the infamous Arnie the Archer while on your camping vacation.
The director will award prizes to your Sims if they organise various activities like parties and games and just generally getting involved with your fellow Sims. Your Sims can then take their prizes home and display them for all to see.
Found in the Gothic quarter of Old town, in shops that sell masks and candles you can have your palm read by this strange lady. Sometimes the the type of reading she gives can alter the mood of your Sim or even of the Sim's whole family.
Revification (LL & SU) - If one of your Sims dies and another Sim in the household pleads for their life but the Grim Reaper turns them into a Zombie, get the family to go to Old Town and visit the Palm Reader, the option for revification should come up. Pay her 200 Simoleons and your Zombie Sim will be returned back to their normal state.
Want to have the best trained pets in the neighbourhood but don't want to put in the effort? Then hire this guy to train your pet. It costs 250 simoleons per point but if your sims can afford it, it will save them a lot of time and effort.
This farmer can give you advise with your vegetables. If you want you can also buy a tonic from him that will make your vegetables grow nice and big.