The women museum (musée des femmes) on Ile de Gorée is very interesting, especially when you ask for a guide. It's right in front of the slave house (maison des esclaves).

Charming christian church in the city center. Just turn 200 m from the road leading from Dakar (on your right you'll certainly see it)

A must for any visit to Dakar! It's very simple to take the ferry out to the island, and the ferry trip itself allows one a nice view from afar of Dakar. Goree is tranquil and peaceful, a wonderful change from Dakar! The former slave house closes from lunchtime until mid-afternoon (and open an hour later on Friday than the rest of the week), so you will want to plan your ferry and visiting schedule around that daily period of closure.

Island is like paradise, but everyone should know its dark history