I have been following the blog http://www.engames.eu/ for some time now and have shared several of the posters published there with my students, who find them helpful in terms of summarizing what they have studied and providing visual help to go over some vocabulary and grammar items. The posters are accompanied by games and / or some exercises too, and I believe this makes it more enjoyable both for teachers and students.
The poster above is a nice example from http://www.engames.eu/ and it also provides some games and exercises. After students revise the theory over the poster, they them practise using defining relative clauses with games such as Defining relative clauses – Penalty and Defining relative clauses – En Garde . Finally , they can do the cloze test too. Defining relative clauses – Cloze test.
I definitely believe your students will enjoy practising with http://www.engames.eu/