Tungnath & Chandrisilla Trek
A well-paved path from Chopta switchbacks 3.5km uphill, gaining 750m in elevation, to Tungnath Mandir, the highest Shiva temple in the world. There are a number of teahouses from which to enjoy the views.
From here a steep trail continues 1.5km further up the grassy bugyal (high-altitude meadow) trail to the top of Chandrisilla Peak at 4000m. Keep an eye out for icy patches that form along the rocks on the path, which can be slippery. From the summit, the Garhwali and Kumaoni Himalaya stretch out before you, with awesome vistas of major mountains including Nanda Devi, Trishul and the Kedarnath group. There's a small temple up here, too.
From Chopta start early (around 7am) before the clouds move in, or head up in the afternoon; leopards (as well as snow leopards) inhabit the area, so it's best to avoid leaving too early from Chopta. If you want to get to Tungnath for sunrise stay at one of the spartan guesthouses there. There are plenty of teahouses along the trek so you don't need to pack food or water.