(a) Yes. (b) No.
In Canada, no, they are not unless you are in the business of being a professional poker or similar game player. On the flip side, the winnings are not taxable. Thus if you have a lottery winning ticket, you are not taxed. This discussion usually leads to a discussion of the difference between a business and entertainment. And also usually leads to a discussion about US gambling winnings and withholding taxes.
The whole area of gambling and taxes is probably a good topic for an FAQ for tax savvy people. Please give us feedback if you would like us to research and write this.