Bunch of Sims 2 questions

Wondering how to do some of these lovely little tricks. I was watching "Sims 2 Circus Tour with Britney Spears" -- here's  a link http://www.youtube.com/watch?v=sMlJ_Og7Bxw&feature=related

Smoke is flying out, sims are rising in the air, up and down, the outdoor decorative flames burst from the ground without attaching itself into a fire, etc. On one of the videos, she even stands on a table or bed, or something and dances on it. I would love some more insight on this, and the feedback would be great.

How is it that you can get a Sim to stand or sit on a bed, table, and desk without it going through it. I have used moveobjects on and boolprop testingcheatsenabled true to move the Sim over to the surface. I've used the modeling hack and dance hack.

In the http://www.youtube.com/watch?v=mWb0U7B_soo&feature=related video, there are obvious custom content additions. Is there anyplace I can download these?

In Womanizer, http://www.youtube.com/watch?v=jTQ-gCz06J8&feature=related during the first 10 seconds I realize she is doing a dance that is not in the game.

How do i get confetti to fall from the ceiling or glitter?

Is there any way / how i can get my sims to or find more dances to add to the game. Does that make sense?

I will update this as soon as I can.