One of the places near Prambanan you could visit is Candi Plaosan, one of the finest ancient relics you can find of the Javanese Buddhist temple in Java.
Its walls, very much like the temples in the area, are decorated with beautiful relief carvings of the time. However, since the kingdom in the area was ruled by the more powerful Sailendra and Sanjaya dynasties, different rulers favoured Hinduism or Buddhism. They modified the structure according to their reign. The story behind Candi Plaosan is very empowering. It was founded by Pramodhawardhani, the daughter of the Buddhist King Samaratungga of the Sailendra dynasty, credited for inaugurating several other major sites like Candi Sewu and the ever-famous Borobudur temple.
You can best visit the temple early in the morning to catch the sunrise as it awakens the dark temple, revealing the beautiful structure in its early lighter colour. If you are not a morning person, you can visit the temple during sunset, as the setting sun closes the temple in a dream-like appearance, ending the day with a piece of history from olden times.