As the DS has an internal Clock & Internal Dates, you are able to have certain things happen every day, or every week. Below, is a list of all of these events, what they give you and how to activate them:

Sandgem Town

Each day, after obtaining the National Dex, there are swarms of Pokémon throughout the Routes of Sinnoh. The Pokémon and place in question changes each day. You can just go to the route and have a look or take a chance that a TV somewhere in Sinnoh tells you, alternatively, you could just go to Dawn/Lucas' sister in Sandgem Town. She will tell you exactly what Pokémon is where

Swarm Pokémon List

Jubilife City

In Jubilife City, there is the TV station, at the reception of the TV station is the Pokémon Lottery. Each day the Number changes. Going from the end, you will get prizes if your Pokémon match any of the Numbers in order. Below are the prizes:

All Numbers Last 4 Last 3 Last 2 Last 1
Master Ball Max Revive EXP Share PP Up Contest Backdrop

Jubilife City

Just left of the Lottery Counter will be a trainer. This trainer will always ask you whether you wish to battle or not. The trainer however changes every day and thus the Pokémon also change every day. These battles will wind up on the television reports too and can be sent via mixing records

Floaroma Town

In the Accessory shop in Floaroma Town, there is a girl in it that will kindly give you a Berry every day. The berries are the berries you find earlier on.

Valley Windworks

Every Friday, a Drifloon appears right by the Valley Windworks. It will appear every Friday like clockwork after ridding the area of Team Galactic. It is at Level 20 so be ready

Sinnoh Underground

Every day, all of the hikers dotted around the entire Sinnoh Underground change the items that they exchange. If you see a rare item, you should try and snap it up on that day, as you do not know when it will appear again

Route 208

Just before getting to Hearthome City is the Berry Master's House. Like many others in Sinnoh, he will gladly give you a new berry each day so keep going back

Solaceon Town

In the house right next to the PokéCenter in Solaceon Town is a news reporter. he will always ask you to catch and show him a Pokémon. The Pokémon he asks for are always Pokémon that you have at least seen so it should be an easy feat to accomplish.
In reward for the Pokémon that you show him, he will give you a reward of 3 PokéBalls of all kinds, except Masterballs, PremiumBalls and CherishBalls

Dive Ball Dusk Ball Great Ball Heal Ball Luxury Ball Nest Ball Net Ball PokéBall Quick Ball Repeat Ball Timer Ball Ultra Ball

Veilstone City

In the south-west of Veilstone City, there is a lady that will happily give your Pokémon a massage. This massage will boost your Pokémon's happiness and it may even find a cool new contest accessory for your Pokémon

Massage Accessory List

Pastoria City

In the west-most house of Pastoria, a lady will gladly give you a berry. These berries are among the new berries of Sinnoh and are fairly rare. Below is a list of the berries that you can get:

Occa Berry Passho Berry Wacan Berry Rindo Berry Yache Berry Chople Berry Kabia Berry Shuca Berry Coba Berry
Payapa Berry Tanga Berry Charti Berry Kasib Berry Haban Berry Colbur Berry Babiri Berry Chilan Berry  

Great Marsh

In the Safari Zone inside the Great Marsh by Pastoria City, the Pokémon in each location each day are changed so you will likely never get the same Pokémon in the same place as often as in the past

Safari Zone Pokémon List

Trophy Garden

In the Mansion on Route 214, after you have obtained the National Dex, you will be able to speak to the owner, Mr. Backlot. By following his conversation each day, he will tell you of a new rare Pokémon that has been found in his Trophy Garden. The Pokémon he tells you will be there for today and tomorrow, but will be replaced after that so you will have to wait for him to call it back again if you want another to catch

Mansion Pokémon List

Valor Lakefront

In the restaurant at the Valor Lakefront by the Grand Hotel, there will be a handful of new trainers every day whom wish to battle with you, they change every day, but are only able to battle between 9am and 11pm so keep your eye on that Pokétch

Celestic Town

In the PokéCenter in Celestic, if you show the man a Pokémon who is incredibly happy, he will give you a Great Ball. A handy thing to get every day

Snowpoint City

In the house to the North East of Snowpoint City. Each day, he will kindly give you a new word for your Vocabulary for you to use in interviews

Sunyshore City

In the north-east of Sunyshore City is a girl that wants you to tell a story. Using words in your vocabulary, if it fits, she'll give you a ribbon. There are 7 ribbons in all and she'll give them to the Pokémon in pole position in your party

Monday Tuesday Wednesday Thursday Friday Saturday Sunday
Alert Ribbon Shock Ribbon Downcast Ribbon Careless Ribbon Relax Ribbon Snooze Ribbon Smile Ribbon

Sunyshore Market

Everyday in the Market of Sunyshore City, the Seal Seller will change the Seals that he sells for the day. Every day there are new seals so be sure to check back every day for the seals that you want

Seal List

Route 221

On Route 221, there will be a man in a house who wants to see a Pokémon of a particular level. If you get a Pokémon of that level to him, he will give you an item, a handy battle item. He gives three items in the succession of which time it is that you have given and then repeats

First Second Third
Black Belt Expert Belt Focus Sash

Pal Park

After getting the National Dex, you are capable of transferring 6 Pokémon per day per Gameboy Advance cart. These Pokémon are then able to be found at Pal Park on Route 221 to capture. You can only do this once per day for each GBA game so make sure to send the right ones over

Fight Area

In the Fight Area, on Saturdays & Sundays, your rival will appear for you to battle. He is at a higher level (Pokémon at around level 60) than before so be sure to practice. This is an easy way for you to level up your Pokémon too

Resort Area

Once you have completed the Master Rank in all contests, you have access to the exclusive club. This club has a few benefits including a daily massage. However, unlike the massage in Veilstone...this massage greatly boosts your Pokémon's happiness, but it does not find any contest accessories. Definitely the place to go to boost your Pokémon's happiness

Special thanks to Paperfairy for helping us compile this list