These are so easy and can be used with any set of vocabulary. Examples are given here in French, German and Spanish.
Start off the session with revising the main set of vocabulary – in the first example this would be school subjects. Revise also other relevant areas of vocabulary. Display all the gathered vocabulary on the whiteboard. For less able students you could actually provide the vocabulary on flash cards and let them pin them on the wall or on to a flip chart. They could even be presented electronically.
Bonjour mardi, au revoir lundi
Bonjour maths, au revoir anglais
Bonjour M X, au revoir Mme Jones
(This one revises days of the week and combines it with school subjects.)
Hallo Oma, Auf Wiedersehen Opa
Hallo Mutti Auf Wiedersehen Vati
Hallo Schwester Auf Wiedersehen Bruder
(Here we are practising family relationships.)
Hola colegio, adios playa.
Hola frío, adios calor.
Hola alumnos, adios amigos.
(This one combines seasons and leisure activities.)
This can be an effective way of linking two or more topics together. It is also possible to allow students to use the dictionary to find more words.