If your Sim goes to several (more than one) of community lots in one outing they can get coupons in the mail if they ate there. Depending on how much it was or what sort of place (Maxis lots rates more money if nicer furniture there etc.) they get different amounts. They also can invite one guest with those coupons. However, after several EPs this will rarely happens. NL feature.
Your Sims can go out in groups and there are two choices. Just for Fun allows you to go out and have fun without any time limits.
The other one you have to make sure everyone's needs are full, having fun, and they may leave you a nice, expensive gift on the porch or a bag of poo. No linear play, just a time limit.
Sims get hearts over their heads and smell the letters when they get a love letter in the mail. They actually have to walk to the mail box to get them or send them. No flipping it over the shoulder, poof.
If you make your vamp lover mad they will pester your Sim if your Sims are seen dating someone else. (Doesn't have to be a legal date) You have the choice to pay them off to leave you alone for awhile. They will also appear in your Sim's house if you made them mad or they love you or whatever. Or you made them jealous. Pay them off, lol.
Vamps turn into bats and can fly to get somewhere. They also fry in the sun or in rooms with windows. If they get out of casket make sure no windows and get them back to casket as soon as you can.
You can manage groups on your Sim's phone and add or kick out anyone you choose. No rules. Eight are allowed to go out in groups, anywhere you like and anyone. Or just one. You do not have to be in a group to go out as group with any Sim you click. Choosing this option does not add this Sim to your group on your phone. It's a choice you can do to have fun and build relationship points.
Sims can prepare and drink juices in Seasons and they all have different effects. Also, on kids for faster homework etc. Helping Kids in TS2 study makes them (once learned) do their homework much faster, and Private school helps that go faster, too. Not just get out early.
Viewing the scare crow (punkin head) in the game will give your Sim a good scare...make sure motives are full, or not too low.
Ghosts can scare your Sims to death. Fun.
If you didn't fill the aspiration by the time a Sim is elder, no worries, you can fill their wants and get to a platinum state (temporary) right before they die and Grim will bring hula girls and get a gold headstone, anyway.
Ghosts won't go upstairs or downstairs (before final patches) to haunt your Sims so move upstairs to sleep etc. if they are keeping your Sims awake and you need that raise. Also, they will kill your Sims eventually. Angry ghosts are the best. If you sell the ghosts' beds they will be very angry.
Deaths in the game were watered down with two different Seasons' patches due to player complaints. So, the ratio of your Sims dying of freezing to death, electrocution of any type, dying in the pool, starvation, illness/flu, fire are almost nil with all EPs and patches installed. But before Sims had a dozen or more ways to die and by many different objects and situations.
If your Sim is sick with the flu (before FT) you could get your scientist (didn't have to be a scientist (just the reward in house) anyone with high enough skills) to create an antidote and cure them. This was important because a cold would turn into flu if not treated and they would die. (Comfort issues were the reason and if those drop too low during illness they could die from other motives due to couldn't get comfort and or stop coughing)
You can influence another Sim (if they are a vamp) to drink the potion from the gypsy (if your Sim bought some) to drink it and be cured. You could cure everyone that way over time except Count and Countess.
Sim kids can show off to others and gain relationship points while showing off, cartwheels, handstands etc. Can be used for fun and relationship building.
Paper can be used as a paper airplane.
In OFB your Sim can build great working toys and or machines that do stuff. Everything they build (except pet bricks) do something.
Kites, Sentry Bots, a vacuum thingy, etc. Flowers (particular ones) assortments can solve all motive problems etc. Sentry bots will zap the Sim who steals your paper etc. Or you can use it to zap the Ex if they show up. lol
Creating 'bad' or not up to par objects can lend to some fun. Like the broken little robot toy. Go ahead have your kid play with it.
Servos used to go beserk and kill your Sims if they couldn't fill their aspirations (wants etc.) Later, patches changed the odds this would happen (nearing the end of the series) probably in those 2 Seasons' patches.
The Servo's recharge animation was changed later in the game..which I never liked the change. I liked it when they got that big shot of energy from the sky.
They have a little thing on their head that if they are broken and you won't fix them and or call a repair man, they will signal one themselves. It's hard to break them, now, too. Fun is gone with later patches due to players who don't like deviant play complained. That's just a fact. All things like this was changed and ratios changed in 2007 for all type of deaths and or anything like that.
Eating at the kiosks in the game (different ones in different EPs) can give your Sim different badges and or raise aspiration depending on which food. (Precursor to moodlets) (Larger buff on those foods..aka moodlet buffs in the making) Not surprised since Ron Humble and The Sims Studio took over TS2 in 2007 right before they created BV. Probably during the time we got two Season patches to change the ratios of injury and deaths etc... in those...yes, I'm not being sarcastic but grumbling how the game changed after that.
Turkey will practically last your Sims all day. (Note a base game feature, not an EP feature like buffs in FT).
I think I have rambled enough and didn't tell you all anything you didn't already know. There is so much in TS2's base game for others to discover, it would take weeks to tell them.