Huge update Thursday I'm betting is the Whacking Day event. Someone from the Simpsons Tapped Out forums tapped into (no pun intended) the game files. It's long, but if you're interested here it is:
Characters:
Gil
Lugash-
Legs-
Miss Springfield-
The Rich Texan-
Agnes Skinner-
Whacking Day (-)
Practice Snake
Red Practice Snake
Green Practice Snake
Yellow Practice Snake
Purple Practice Snake
Ninja Homer - part of the "Whacking Day" update
Unwhackable Snake - part of the "Whacking Day" update
Buildings (-)
Lugash's Gym
Legitmate Businessman's Social Club
Skinner House
Swanky Fish - as part of an episode tie-in
Springfield Mall
Sprawl-Mart
Duff Stamium
The Frying Dutchman
Decorations
Camp Fire
Camping Tent
Ficus Plant*
Ice Cream Cart*
Krusty Themed Totem Pole*
Manhole- - 200
Santa's Little Helper Topiary- - 1800
BBQ- - 5
Whacking Day Stick Stall-
Whacking Day Mugs / Whacking Day Mug Stalls-
Whacking Day T-Shirt Stall-
Whacking Day Banner-
Snake Egg-
Snake Stump-
Hollow Snake Stump-
Snake Rocks-
Snake Speakers-
Snake Statue-
Whacking Day License-
Expert Whacking Day License- (Enables players to whack up to 5 snakes in friends' towns each day).
Elite Whacking Day License- (Enables players to whack up to 10 snakes in friends' town each day).
Basket of Eggs- (Snake Eggs to place in friends' towns)
Memorabilia (-)
The user that posted the information said that there may be "Mini Games" added to the game that could be included for each building. The user said the coding works like the Homer's Buddha/Mystery Box/Leprechaun Tap; a Random # is generated, then used to determine the prize gained. The odds of winning a prize from a building are 66%, with odds of each listed item being:
1st Item Listed: 5%
2nd Item: 10%
3rd Item: 14%
4th Item: 17%
5th Item: 20%
which equals 66% total odds. The other 33% of the time does not result in a prize. Each item has a cost of 1 assigned to it, presumably the cost of playing the 'mini game'
The items listed for each building are:
Simpsons House: Krusty Doll, Boat picture, Slingshot, Lisa's Sax, Ned's Lawn Mower
Flanders House: Bible Card, Religious Board Game, Last Supper, Bible, Maude Picture
Power Plant: Carbon Rod, Suit Helmet, Security Badge, Demotivation Plaque, Burns Painting
Kwik-E-Mart: BuzzCola, Squishee, Play Dude, Old Hot Dog, Laramie Cigarettes
Springfield Elementary School: Apple, Globe, Malk, Dodgeball, Beethoven Bust
Willie's Shack: Rake, Mop & Bucket, Kilt, Flask, Bagpipes
Frink's Lab: Beaker, Test Tubes, Hamburger Earmuffs, Brain Helmet, Push Popper
Krusty Burger: Milk Shake, Mother Nature Burger, The Clogger, Employee Hat, Employee of the Month
First Church of Springfield: Collection Plate, Podium Banner, Book of Hymns, Bible, Stain Glass Saint
Van Houten House: Alf Pogs, Pajamas, Bonestorm, Baron Von Kit, Krusty Walkie Talkie
Cletus' Farm: Old Boots, Roadkill, Shotgun, Musical Jug, Geech Smell Hound
Android's Dungeon: Bootleg Videos, Mary Worth Phone, Ultimate Pog, Angry Dad Comic, Radioactive Man Comic
Lard Lad Donuts: White Donut, Pink Donut, Chocolate Donut, Plain Donut, Purple Donut
Moe's: Pickled Eggs, Bar Stool, Cockroach, Beer Mug, Flaming Moe
Town Hall: Mayor Sash, Vote Quimby Sign, Town Charter, Money Brief Case, City key
Retirement Castle: Pill Tray, Bingo, Ointment, Dentures, Sex(?) Tonic
Police Station: Empty Donut Box, Wanted Poster, Wiggum Police Hat, Wiggum Gun, Wiggum Badge
Springfield Downs: Discarded Wager Tickets, Ticket Stub, Track Rabbit, Dog Jacket, Winners Wreath
Luigi's: Pizza Box, Chef's Hat, Bottle of Wine, Accordion, Picture of Italy
Springfield Penitentiary: Lunchtray, Taser, Prison Jumpsuit, Straightjacket, Die Bart Die
Gilded Truffle: Matchbook, Valet Parking Stub, Fancy Menu, Tin Foil Swan, Fancy Wine
Duff Brewery: Duff, Duff Lite, Raspberry Duff, Lady Duff, Tartar Control Duff
Springfield Library: Silverfish, Turtle, Old Computer, Mables Table, Audiovisual Terminal
Springfield Observatory: Meteorite, Buttzila, Microscope, Doomsday Whistle, Telescope
Episode tie-ins (-)
"Whiskey Business" - 'Respectable Moe' will be added as a costume for Moe.
Unknown - Swanky Fish will be added to the game.
Whacking Day Prizes (-)
Fort Sensible
Sleep-Easy Motel and Miss Springfield
Expert Whacking Day License
Gymnastic Lisa and Balance Beam
Snack Rocks
Snake Statue
Duff Stadium
Pet Snake
Bare-Chested Willie
Springfield Coliseum and Tatum
After the player has won all the prizes, he/she gets a game notification saying "Congratulations, you got all the Whacking Day prizes! Continue to whack snakes and you can win Whack Boxes that contain donuts and money."
At the end of the Whacking Day text, "You've just found the super secret bonus!" appears. From this the player can win:
30
75
150
200
250
Whacking Day tasks/quests (-)
Make Ninja Homer Smash Up Flanders Home
Make Ninja Homer Twirl Whacking Stick
Make Ninja Homer Polish Stick for Whacking Day
Send Homer on a Snake Hunt!
Whack Snakes
Make Ned Send Snakes back to Hell
Make Cletus Shoot Snakes
Send Lisa to Release Snakes from Another Town
Make Milhouse Get Bullied a Snake
Make Skinner Hide From Lisa
Make Willie Inject Himself with Snake Venom
Make Homer Snake Hunt!
Make Ninja Homer Fake-Whack Pretend
Whacking Day notifications
In-game
In the Whack Box you found: Congratulations, you got all the Whacking Day prizes! Continue to whack snakes and you can win Whack Boxes that contain donuts and money.
You are now licensed to whack 5 snakes in each friend’s Springfield every day so if you’re a hermit, start making friends!
You're out of snake eggs right now. Whack snakes to find more!
Tap on free areas of ground to place snake eggs in your friend’s town.
Friends have planted {0} snake eggs in your town. Tap on them to hatch extra snakes.
Congratulations! You are now licensed to whack 10 snakes in each friend’s Springfield every day! Springfield is overrun with too many snakes! Catch a couple before releasing these.
Enter Baton Mode and tap to whack snakes and collect rewards.
Place snake eggs in friends' towns for them to hatch. Some snake eggs contain donuts!
Win up to 10 amazing prizes for whacking snakes. Just like in real life!
The event ends May 2, 2013. Get whacking!
You whacked {0} snakes and won a new prize! Find your prize in your inventory.
[edit]Push
{0} has released some snakes in your Springfield!
{0} has planted snake eggs in your Springfield!
Springfield is overrun with snakes. Better get whacking!
Snakes are all over your Springfield, just begging to be Whacked! (After 24 hours)
{0} has sneaked into your Springfield and released some snakes!
[edit]Other
With the Whacking Day update, a "Whacking Day Box" will be added. The player will win either donuts or cash from it.
The Whacking Day song:
Oh Whacking Day!
Oh Whacking Day!
Our hallowed snake skull-cracking day!
We'll break their backs!
Gouge out their eyes!
Their evil hearts we'll pulverize!
Oh Whacking Day!
Oh Whacking Day!
May God bestow his grace on thee
Ninja Homer: *sobbing* I love this time of year.