As a (hopefully temporary) PAYG instalment taxpayer, I noticed that the Australian Taxation Office has started a trial for accepting payment of tax bills via credit card. This means that if your credit card is linked to a rewards system, you may be able to earn rewards just by paying your tax.
Sadly, there is a catch. There is an additional card payment fee which is charged for credit card transactions–up to 1.02% currently. Boo.