Here is a quick list of what's actually going on now:

• 1996 November 7, Delta II, currently operating in Mars orbit. Mars Global Surveyor (Nasa).
• 2001 April 7, Delta II, currently operating in Mars orbit. 2001 Mars Odyssey, Mars Surveyor 2001 Orbiter (Nasa).
• 2003 June 2, Soyuz-Fregat, currently operating in Mars orbit. Mars Express (ESA), Orbiter Mars Express and a Lander named Beagle 2.
• 2003 June 10, Delta 2 (7425), currently operating on the surface of Mars. Spirit, 2003 Mars Exploration Rover 2, MER-2, MER-A, Mars Surveyor 2003 Lander/Rover A (Nasa).
• 2003 July 7, Delta 2 (7425), currently operating on the surface of Mars. Opportunity, 2003 Mars Exploration Rover 1, MER-1, MER-B, Mars Surveyor 2003 Lander/Rover B (Nasa).
• March 2, 2004, Ariane V, currently in interplanetary cruise. Rosetta (ESA). Was scheduled for launch in January 2003, as Mars/asteroid/comet mission, will flyby Mars for gravity assist on August 26, 2005, to finally reach and land on Comet 46 P/Wirtanen in 2011.
• Mars Reconnaissance Orbiter, Mars Surveyor 2005 Orbiter (Nasa). Arrived at Mars on March 10, 2006, inserted into highly-excentric orbit; now in aerobraking phase scheduled until November 2006.

For future Martian springtimes:

• 2007 August. Phoenix - the selected Mars 2007 Small Scout Missions (Nasa): An in-situ volatile and organic molecule survey (LPL/Univ of Arizona).
• 2009 December Mars Science Laboratory, Mars Smart Lander, Mars 2009 Mobile Scientific Laboratory (Nasa).: Formerly scheduled for 2007, the spacecraft is now to be launched in December 2007, and to arrive at Mars in October 2010.
• 2009 Late Phobos-Grunt (Russia). Scheduled sample return mission to Martian moon Phobos.
• 2009 Late Beagle 2: Evolution (ESA). Mars Lander.
• 2011 Mars Scout 2 (Nasa). A mission succeeding and extending the 2007 Mars Scout, Phoenix; details to be defined. Mars Beyond 2009 page (JPL); Mars 2003 and 2005 page (NSSDC)
• 2011 Exo Mars (ESA). Will include an orbiter and a descent module that will land a highly mobile rover, weighing up to 200 kilograms, on the surface of Mars.
• 2014 Mars 2014 (Nasa; possible participations from France and Italy) Possibly first sample return mission. Mars Beyond 2009 page (JPL); Mars 2003 and 2005 page (NSSDC)
• 2016 Mars 2016 (Nasa, international?; under study). Possibly another sample return mission, or orbiters, landers, rovers. May include a Mars Astrobiology Field Laboratory, or Deep Drilling or other technologies. Mars Beyond 2009 page (JPL); Mars 2003 and 2005 page (NSSDC)