A Russian T-62 unit engaged some Georgian T-72s. I have a report called iirc The Tanks of August, I'll dig it up.
EDIT: It's available right here, but only in Russian unfortunately.
http://www.cast.ru/comments/?id=351 I'll translate and summarize any relevant parts myself in a little bit.
Ok so on August 8th 3 Georgian T-72s opened fire on BMP-2s at the entrance to the Russian peacekeeping battallions camp. The BMP-2s were destroyed, with response fire from RPGs disabling one of the T-72s and forcing back the other two.
Three more T-72s were killed by South Ossetian forces in the center of Tshinvali, one of them personally by the head of state security of South Ossetia, by RPG-7s.
At least three T-72s were abandoned by the 42nd Infantry Btln of the Georgian forces, along with other armored vehicles and equipment, when Russian Su-25s airstrike killed over 20 and wounded many more.
Two Georgian tanks were abandoned on August 8th on the Zars road, tanks No 110 and 125, and were detonated by Russian troops.
Two Russian T-72s from the 141st Independent Tank Bltn broke through to the peacekeepers camp, and participated in combat there. One of the tanks was destroyed, the other ran out of ammo by nightfall of August 9th.
On August 10th a T-62M of the 71st MRR, 42nd MRD was destroyed for unclarified reasons. (other sources talk about a tank engagement between some Georgian T-72s and the T-62Ms, with 1-2 Georgian tanks destroyed in the fight)
During the advance movement of the 693rd MRR, a T-72B (No 321) and two BMP-2 were destroyed by RPG fire from Georgian forces from the 2nd Infantry Brigade, and some reservist formation.
4 T-72s (No's 206, 207, 208, 209) were captured at the Senaki base of the 2nd Infantry Brigade, by the 693rd MRR. 2 were destroyed on the spot, 2 evacuated to Abkhazia.
An unspecified number of military equipment was captured on 3 Georgian Army bases near Gori. Presumably the bulk of captured tanks was from there. Around 20 T-72s were destroyed near Gori after being captured, the rest were evacuated. 65 tanks were captured after the end of hostilities.