The Mars Odyssey orbiter will be listening for radio signals from the Mars Phoenix Lander. Having ceased communications near the end of 2008 with the onset of the Martian winter, the Phoenix lander is extremely unlikely to have survived, but if it somehow manages to come back to life with the start of the Martian spring, it will be sending out signals that Odyssey should be able to pick up. The Phoenix lander was not designed to survive the Martian winter, so it would be extremely impressive if Odyssey picks up signals from the lander: it really would be like a phoenix in more ways than one (the other way being a resurrection of a cancelled Martian lander project).
There most likely won’t be any signals from the Phoenix lander, though, but this is still an opportunity to remember the impressive achievements it made.