Fly
##Fly ByBy far the simplest (but not cheapest) way to get from Dulles to Charlottesville is to fly. United Express operates several IAD-CHO nonstops, each under an hour on a regional jet. This flight, however, would cost a few hundred dollars when booked separately and on short notice.
Rideshare
##Rideshare ThereThere are groups where people can arrange rides like Hoo's driving? Hoo's riding? NOVA on Facebook, which caters primarily to University of Virginia students. UVa is a large university and there is a fairly steady stream of people going back and forth between the campus and the Washington area, although this will drop off dramatically once final exams end next week.
Train
##Train DullesDulles, unfortunately, is not located near any passenger train stations. For heading to Charlottesville, which is to the southwest, your best bet would be to take a taxi to the Manassas station (MSS)— there is no good way to do this via public transportation— and take an Amtrak from there to Charlottesville (CVS). Services at the station are very limited and there are only three daily trains, so be wary of timing; you can buy tickets online and have the barcode emailed to you or delivered via their mobile app. The coach seats on the train almost never sell out except on holiday weekends, but buying tickets in advance may save you some money as well as peace of mind.
Bus
##Bus ThereThere are no intercity bus stations near Dulles, either, and none of the bus options is especially convenient. Your best bet is probably to make your way to Washington (see directions linked above), where you can get Greyhound service from Union Station for under $40 if you book in advance.
Rental car
##Rental car ToTo get around anywhere outside the largest cities in the U.S., you're almost always best off if you have a car, so consider renting a car. The drive from Dulles to Charlottesville takes about two and a half hours and would be almost entirely on well-maintained expressways.
Taxi/Airporter/Uber
##Taxi/Airporter/Uber ThereThere are a number of so-called "airport limousine" services which operate vans or shuttle buses from Dulles to Charlottesville. These have the advantage of direct and relatively quick service, but they can be expensive, and there is no easy way to compare prices or quality among the numerous options. From what I can tell, the lowest you can expect to pay is about $180 plus a tip for the driver.