Whenever I introduce equivalent fractions to my students I pull out the fraction bars. The fraction bar sets I have go from 1 whole to a denominator of 12. I have my fraction bars in individual baggies, so that I can give each group a bag of fraction bars. (I try to pull these out the day before and have them sitting out ready to be used. This saves time during the lesson.) First, I pass out the bags of fraction bars and ask the students to sort them by color. Next, I begin with the 1/2 fraction bar and model with the students how to find an equivalent fraction. I then let them use trial and error to find the remaining fractions. After this, I write all the fractions we found on the board. Next, I repeat this process with 1/3 & 1/4 bars. Many times the student will realize that there is a pattern happening. I will then talk about the pattern with the class and then announce that we are going to learn how to find equivalent fractions using math.
This process only takes about 15-25 minutes from passing out the bars to picking the bars back up. I hope that if you don't already use manipulatives in your classroom, that you will pull them out and try them. In my classroom, the reward outweighs the "trouble" of getting them out!