Here's a fun time PowerPoint activity on zero and first conditional clauses. It should accompany a grammar presentation on first conditional clauses to contrast type zero and first conditionals. The context of the questions is in the "school days" theme. The exercise is designed as an ESL grammar competition. Just bring two students to the front and make them race! The timer, correct and wrong answer slides will bring fun to your class.
The exercise is relatively light for good students. It ideally fits a grammar lesson in pre-intermediate or intermediate level classes. It covers the basic concept behind the two conditionals and some conjunctions used with conditionals.