The best adventure park close to Bucharest. Edenland offers a range of adventure trails for kids (and adults, for that matter) of all ages, as well as paintball, archery, horse-riding and other outdoor activities. You will need your own transport to get here, for while a taxi will be happy to take you, it might be tricky finding one to bring you back again. They even have family-sized tree houses for hire (390 lei per night) if you want to sleep here.
Adults 50 lei (for three hours), children (aged 11-18) 40 lei, children (aged 4-10) 30 lei. BIke hire 30 lei for one hour.