Below are a few tidbits you may not have discovered. It's incredible the details the developers think of adding.
1. Teddy bears can be put into cribs in buy mode.
2. Pregnant sims who eat apples or foods made with apples tend to have boys. Same goes for watermelons and girl babies.
3. A baby's sex can be determined before birth by a Sim in the medical career in at least the fifth level. This is found under the friendly interactions menu.
4. Click on your lights to change the color of lights and their intensity.
5. Sims can age anytime not just at the end of the age stage. Buy a birthday cake and pick the Sim you want to age to blow out the candles.
6. Childish sims can fish in pools.
7. Good sims can donate to charity. Click on a mailbox with a good Sim selected.
8. Rock stars will be cheered or booed when seen in public.
9. Handy sims can wire speakers so the whole house hears music when radio is on.
10. Sims in the Criminal career cannot be robbed.