Participation is a part of the grade and I make kids keep track of what they say and when. I require students to participate five times each card marking for a required stamp [part of their grade] with the possibility of getting more as extra credit. I am very strict on what constitutes as participation with one word answers not accepted.
I sign at the end of the hour when I can still remember what they said!
This requires that they get EIGHT stamps in the course of a card marking, which is six weeks for us. But you can edit it to modify my directions, expectations, etc.
Our school year is divided into six card marking, so I increase the expectations (# of stamps required) each card marking. This is Forms 1-3, and Forms 5-6 are sold separately.