Provide the students with a labeled diagram of parallel lines and one or two transversals. Have them work in groups to determine which of the angles are congruent. Then have them come up with the properties for angles and parallel lines.
Have students do a written assignment

Tic-Tac-Math

 Put students in teams. You can use as many teams as necessary for the size of the class. Three to five per team works well. Assign each group a symbol (x's, o's, +'s, -'s). The teacher places an x and o chart on the board. The size of your chart will depend on how many teams you have. For two or three teams a line of three symbols(vertically, horizontally or diagonally)to win works well. For more than three teams you may want to have a line of four symbols which means you'll need a larger grid. The teacher will pose a question. As a team they must come up with an answer. The team leader will bring the answer to the teacher to be checked. If they are correct, they can place their symbol on the chart. With four teams you might want to allow two teams to place their symbol on the chart.