Here is a recipe I have been making often because of the heat. It is fast, easy, and does not use the oven. :)
3/4 c. butter, melted
3 c. crushed graham crackers (about 1 1/2 pkgs.)
2 1/2 c. powdered sugar
1 1/2 c. peanut butter
1 1/2 c. chocolate chips
Mix all ingredients, except the chocolate chips. Pat into a 9x13 pan. Melt the chocolate chips and spread over mixture. Refrigerate 30 minutes or until firm. Cut into squares.