I received several emails with corrections and additions to the future space events list I posted yesterday (follow the link on the navigation bar to the left); thanks for those! Corrections especially are always welcome -- I hate to be a source for bad information.
One of the emails was from New Horizons Principal Investigator Alan Stern, who clarified the dates on their Jupiter and Pluto encounters and mentioned that today is the day that New Horizons passes Mars' orbit (not that Mars is anywhere close to New Horizons right now). That's pretty quick work -- much faster than the time it took Mars Reconnaissance Orbiter to get there! Of course you have to be going much more slowly if you want to stop, as Mars Reconnaissance Orbiter did -- New Horizons can't be stopped, ever. So I tossed this date into my list, and also added in there the future dates on which New Horizons will pass the orbits of all the other outer planets.