I guess this can be a bit tricky, I've had people tell me about problems they have with it. I made a dance floor and put dancing on my bar, didn't think it was that big of a deal.

You would use the trigger box. Click on the new object button, search for trigger, click on it, then click create. I would first scale it to the size and rotation you want, then set it to the location you want. Go to the script tab and select the script Dance (or whatever kind of dancing you want - Dance Country, Dance Erotic). Under the state tab, click the little Advanced box. Then find and check Invisible and Trigger.

If you require additional help, please let me know and I will come help you.

Here's some notes on dance floors and clickabel jukeboxes

Dance Floor
Create a Trigger Box in Prop Editor
Re-size it and place it where you want
Make sure it goes all the way to the floor and preferably to the ceiling
Script the trigger box with one of the following
Dance
Dance Country
Dance Exotic (have not tested this one yet, but could be fun *W*)
State (with Advanced checked)
NOT collidable
Check Invisible
Check Trigger
Un-lock it and exit Prop Editor
Done

Juke box
Create a Jukebox in Prop Editor
Click (check) Advanced in Prop Editor (upper right of the prop editor window)
Script it with Cached Clickable Web Image
Put nothing in the Image URL
Put the address of the music page in Click URL
It should be an address that you can put in your browser and the music starts playing without further input
Turn on/off this feature should NOT be checked
Collidable should be the ONLY state checked, and even that is optional
keeps ppl from walking through your jukebox, but does nothing either way for operations
Un-lock it and exit Prop Editor
Done


NOTES:
Dance floor will start you dancing as soon as you walk on it
Each person in the zaby will have to click on the jukebox to hear the music
Everyone will hear the same music at the same time
It will start up a media player and start streaming the music
You can turn the music off by stopping the media player