La donna é mobile
(by Giuseppe Verdi)

I have treated his aria alittle disrepectful, I know (but I hope it may be fun to sing, anyway).
Observe that the melody is not always in T1, but moves around between all the four voice parts.


On 

http://www.azopera.com/learn/synopsis/rigoletto.shtml

you can read a synopsis of the opera.


On

http://www.operaheb.co.il/operas/arias/rigolett4.html

there is a tranlsation to English.


On 

http://www.aria-database.com/cgibin/aria-search.pl?265a

there are a lot of other facts about this specific aria.