Practises: almost anything
This classic classroom game is guaranteed to wake up the doziest class.
It can be used for anything from learning the alphabet to revising irregular verbs. There are many variations dependent only on the teacher's imagination.
The basic idea is that the teacher covers the whiteboard randomly with words or letters. If, for example, you are teaching the alphabet, you might cover the board haphazardly with all the vowels and some of the more problematical consonants. It's a good idea to repeat some of the letters, perhaps in upper and lower case.
The class is divided into two teams. One team is given a blue whiteboard marker. The other team is given a red marker. The teams line up on either side of the board with the front students holding the markers. The teacher calls out a letter and the front students try to locate it and draw a ring round it. Change students every call or every three calls etc. The team with the most number of rings at the end wins.
Some possible topics (can be mixed):