This might be a better one for the garden or park, me and my brother got into a lot of trouble for breaking items at home trying to do keepy ups in the house.
This is not just a footballing skill activity! There are a number of different items that you can use and other body part too.
If you don't have a ball you could use rolled up socks or a toilet roll. If you do not have a racket or bat ask you parents if you can borrow a sauce pan (make sure its not to heavy). You can do keepy ups using your hands/feet/knees.
Your aim is to do as many as possible but if you can keep the item in the air for 30 seconds wthout it dropping you have done an amazing job. If you are finding it difficult then you can allow yourself 1 or 2 bounces between it hit of the ball to help you improve your skills.