Humans have been throwing things at Mars since at least 1960 (I’ve never been convinced that we really know all the unsuccessful Soviet space missions). The first US mission to Mars was launched in 1964, but Mariner 3 didn’t make it.
Mariner 4 was the first to get there,
entering Mars orbit doing its flyby on July 15, 1965.
After a bunch of failures (the Mars Curse in action) and a couple of successful orbiters, Viking 1 landed on July 20, 1976, ten years after the first orbiter reached Mars, and its twin Viking 2 landed shortly thereafter.
The next batch of missions, both ours and Soviet, failed (see above, Mars Curse). Mars Global Surveyor entered orbit in 1997, and sent back data for ten years, far longer than expected. Mars Pathfinder landed in 1997 and sent the rover Sojourner out to look around.
Mars Odyssey entered orbit in 2001, and is still sending pictures home.
My favorites until earlier this month were the Spirit and Opportunity rovers, wandering Mars since 2004. Planned to run for 90 Martian days, Spirit chugged on until 2010, and Opportunity is still roving.
The Mars Reconnaissance Orbiter has been in orbit since 2005, with the HiRISE sensor sending back some incredible high-resolution images (end of mission planned for 2010, but still going). (The missions that have gotten there have done amazing things.)
The Phoenix Lander studied Martian water in 2008-2010.
I watched Curiosity land (on Mars! from a tent! on a hand-held computer! truly we live in the future), and so did the Mars Reconnaissance Orbiter.
Not only did they drop Curiousity safely, NASA’s been doing a brilliant job with the social media and internet. Curiosity is on twitter as @MarsCuriosity, and can be tracked here. This educational/citizen science website is wonderful: Be a Martian.
We’ve done amazing things, and learned a lot: just compare the Mariner 4 images to HiRISE or Curiosity’s pictures. I can’t wait to see what we do next.