Historian: Actually Cassini has been at Saturn for a long time. Launch was 15 Oct 1997, followed by a cruise with two swingbys of Venus and one swingby each of Earth and Jupiter to get gravity boosts before arrival and orbit insertion at Saturn 1 July 2004.
Physicist: The prime mission 2004-2008 was extended to include an equinox mission 2008-2010 and a solstice mission 2010-2017. Cassini's "Grand Finale" will end 2017 with a plunge into Saturn's atmosphere. The ESA Huygens lander descended to Saturn moon Titan 14 Jan 2005.
Historian: There is a nice timeline on the science at NASA Cassini home page (scroll down a bit) with more details about these missions. There is much to explore there and at the NASA Cassini home page. There is also much to explore via the well laid out ESA Cassini-Huygens home page; be sure to take the "In depth" link in the right column.
Physicist: Saturn's rings gave us an icon hard to avoid in daily life. In return parts of humanity now reside on Saturn's moon Titan in lander Huygens and soon parts of humanity will plunge into Saturn's atmosphere in spacecraft Cassini. Here at home our humanity expands with views sent back by Cassini and Huygens and by knowledge and skills gained from the mission.
"Four Days at Saturn" video [link]
NASA Cassini mission home page [link]
Science at NASA Cassini home page [link]
ESA Cassini-Huygens home page [link]