Checkout this amazing polka dot cake made by Anj at Snowy Bliss. I love the polka dots peeking through the cake pieces. What an adorable idea.
The full how to make tutorial can be found at: http://snowybliss.blogspot.com.au/2011/09/polka-dot-cake.html
Decoration essentials from Bickiboo:
Polka dot balloons - Purple, orange, black
Tissue paper pom poms - orange, purple
Polka dot straws - Orange, purple and stripe black straws
Divine twine -black, orange, purple
Black tie tableware set