Enjoy a half-day hike on the Holy Mountain of Tbilisi.
Take a stroll from Vake to Turtle Lake (can also be reached by cable car, but walking is nicer), then continue upwards in the direction of the Mtatsminda park. Get off the beaten path along the way and find a little treasure chest with mind games and items to remind you that you're in the Caucasus. Along the way, you will have lovely views of various parts of Tbilisi. After you find it, you can continue to the Mtatsminda amusement park and - if you're feeling energetic - to Narikala fortress.