It is located a bit out of the centre of Jakarta, in East Jakarta, which is much needed because it stretches over 250 acres. The main focus of the park is to get a glimpse of Indonesia's 26 provinces (at the time of building there were 26, now there are 33 provinces), which all have their own unique cultural identity.
All 26 provinces have a separate pavilion where you can see the province's traditional house, clothing, instrument etc. Even though the park's name uses the word "Mini", the houses are actually not small (it is not like Madurodam in the Netherlands). The houses are life-size replicas with some of them open to the public so you can actually go inside. Some provinces' pavilion also have scheduled performances of their traditional dances.
Besides the houses, there are also a lot of gardens, museums and an Imax Theatre which besides occasionally screens blockbuster movies, also has a movie on Indonesia's landscape called "Beautiful Indonesia". There is also a cable car you can ride on to get a bird's-eye view of the park.
I recently visited Taman Mini, and the shame thing is that it could use some fresh paint...but nevertheless, it is a nice place to get acquainted to Indonesia's rich culture without leaving Jakarta. But if you want to experience the genuine culture, of course, nothing beats going to the actual provinces.
If you do plan to explore the whole park, you might think of freeing your agenda for a whole day and also, bring a car!