Hike - There's limitless great hiking in the whole area. From Sisian to Tatev not on the highway, from Tatev to Kapan on the backroads, around Shikahogh Reserve, all around Yeghegnadzor, Noravank Canyon, in the Smbataberd-Arates-S. Sion valleys, and elsewhere.
Bike - Biking is a good way to get around the backroads of the region, and highways if you don't mind sharing the road with cars. The Tatev - Kapan backroad is a great one, and so is the area from Yeghegis to Herher.
Hotsprings/Spa - Visit the spa town of Jermuk, where much of the country's mineral water comes from. The town is full of Soviet hotels and sanatoriums, some of which have been renovated to high standards. The countryside at this very high elevation resort is worth the visit as well, with canyons, forest and wildlife to explore.