Watch "We can be heros". That's his first series. Was sooo good. Its the same basic idea of him playing a bunch of different characters but they're all nominees for Australian of the Year. Its where the two brothers started.
Summer Heights High is by far the funniest series though. Probably the best because here in Melbourne we know a lot of the kids and we recognise the schools. Eg. The principal is the real life principal of Camberwell High where my first girlfriend went to school.