If you like quiet time surrounded by flowers and greenery, hang out at Garden of Dreams in Thamel. If you like Garden of Dreams, you'll love Siddha Pokhari and Shivapuri Nagarjun National Park, both just a short drive away.
If museums are on your list of things to see in Kathmandu, then you might want to head to Narayanhity Palace Museum. If you want to see more of the museums in Kathmandu, National Museum of Nepal and Natural History Museum aren't far.