What country can I work abroad for only 2 months without any visa and stuff?

You need a visa to work in any foreign country. But many countries have exchange programs or if you find a sponsor, you can get a work visa for a couple of months. Then there is always a student visa.

Your best bet would probably be to get a working holiday visa. You could get one for Singapore. New Zealand or Australia.

You could also look into some volunteering opportunities through an organization.

None whatsoever

NB Sydney's a city, not a country

Australia -- no
japan -- no

brazil -- try their immigration website

Ummm I don't think no country would let you work without a permit

Nowhere