Verkhny Lars-Darial Gorge border crossing
The Verkhny Lars-Darial Gorge border crossing is the only border crossing between Georgia and Russia. Since July 2011 is was opened again for everybody. It connects Tbilisi and Vladikavkaz via the Georgian Military Road which is closed in winter.
You cannot walk over this border, therefore you have to hitch. In the summer season a lot of Russian tourists pass through, but out of season it can be very quiet. A few trucks, mostly from Armenia are transiting here.
Local cars going to Vladikavkaz are often full or don't want extra hassel with a foreigner and Georgians cannot cross the borders without a visa.
Try to befriend the border officials, they can help you to get a ride. In fact n0id waited for quite a while even though a local construction worker flagged down cars and asked them to take him, until eventually a higher ranking officer ordered the guard of the first check-point to find a car for him which took 2 minutes.