Visit Ibadan, Nigeria, only if you have to. Ibadan is enormous, ugly and plagued with crime, and there are few good places to stay.
If you do find yourself in Ibadan, visit the Dugbe market (one of the country's largest) and the University of Ibadan. The university guesthouse also has a small market space where local traders take cloth and other items (this market is less daunting than Dugbe, but it doesn't match Dugbe's variety). The University of Ibadan area once was known for its bookshops, but this is no longer the case, and the university's zoo should be avoided at all costs, as it is awful and the animals are kept in poor conditions.
For a view of Ibadan's old, brown stucco buildings, climb Mapo Hill in the old quarter of the city. 80 mi/130 km northeast of Lagos.