Hi. We would recommend the following:
Meia Praia Beach - 3kms of lovely white sand - great for kids and adults alike.
A trip to the Grottos - visit using a local fishermans boat
Dolphin Viewing trip from the Marina - fast and exciting boats get up close to local dolphins
Glass bottom boat - fast hydrofoil boat trip from the Marina to view the local sealife
The Golden Chapel - exactly as it sounds a stunning chapel in the centre of Lagos completely gilded
Lagos Zoo - small family zoo just 10 mins by car or bus outside of Lagos
A walk around the old town, moorish town walls and entrance ways leading to small cobble lined roads, many shops, bars and restaurants to explore.