Babies love music and movement. Rhythm comes naturally, so play a cd and dance and clap and move around and the baby will love it. In my experience, dancing and singing with children provides endless hours of entertainment.
Simple toys will entertain 11-month old babies. You can give him or her safe toys that can be banged against each other to produce some sound. If it's a nice day, you can also let the baby play in the grass in the compound or take him or her to the park.