Don't go too far to the largest lake in Indonesia 😁 go to Danau Sarangan, it has a historical role in Indonesian independence struggling in the past 😉.

Yes, I know Toba Lake, been there in 2009, it has an annual event which is usually conducted around August, something like festivals and sports events. The best thing about this lake is the Samosir island and the views of the hills that surrounded it.