You might find some info from the art shops at the Bras Basah complex (Art Friend is the biggie, but there are a few others). The community centres do some classes too:
http://www.pa.gov.sg
If you are interested in pottery, Boon's pottery in Tanglin mall organise good classes (I used to attend before my finances tightened!) - they hold them in the mock-tudor looking building down the road (where Dan Ryans diner is), but you have to go into the shop to arrange them.
Don't know about dancing I'm afraid - I have 3 left feet (yes, my dancing really is that bad
)