I don't have much information on Holy Thursday, except that it is called "Big Thursday" and most Georgians go to church, but devout Georgians go to church every day of Holy week anyway. I have also been told about a non-Christian tradition on Holy Wednesday. Children and young adults run through and jump over a bonfire in order to make bad things (spirits, illness, bad luck?) go away. Today it is more of just a fun tradition for kids than anything else.
My neighbor was kind enough to let me dye eggs with her after my mass on Good Friday. She did all the hard work crushing and boiling the branches, but let me join in for the fun part.