There are a couple activities that I use to engage my students in the practice of speaking Spanish. They are a couple games that take me out of middle of the conversation and get them interacting in the target language with each other. Not only that, but they have fun while doing it. If you are looking for a way to get your students talking, check out the activities below:
1) Rey del Mundo is a free instruction sheet for a fast paced game that gets students dialoguing in the target language.
2) Human Bingo is an activity that prepares and requires students to dialogue in Spanish. It is easily adapted, though, to any second language classroom. It also helps students in the class get to know each other better! Check it out at my store. $$