What can you do in 30 seconds?
Find something in your house that is small and there are lots of. You could use pasta, pom poms, rolled up paper or anything similar. You then need a tub or a saucepan or a bucket and something to time 30 seconds on.
Guess how many of your small items you are going to be able to get into your container in 30 seconds. Have a go and count how many. Then repeat this activity a few times, trying to get more and more into the container.
If you are brave enough to go out in the cold you could use goalposts and a football and see how many goals you could score in 30 secs.
You could also challenge someone in your house to have a go aswell. Did they beat you and get more?