Audrey - your best source of what is going on onboard is your "Princess Patters" newsletter which is delivered to your cabin everyday. It lists all the activites along with the entertainment options.
Skywalkers Disco doesn't really get jumping until after 11pm. The DJ on our cruise played alot of the techno-funk type music . Skywalkers does do theme nights(60's, 70's 80's etc). The main lounge for dancing and activites is Explorer's Lounge - there is a dance band, and this is where they do Karoke, Talent shows etc.
The Wheelhouse Bar is a great place if you want to relax with a drink, listen to some good music and dance.
Don't miss the Island Night Deck Party and the Midnight Champagne Waterfall.