Saw a duo in Indiana about 25 years ago (yes...I'm THAT old!). Two fellas, one on guitar and the other on various and sundry instruments of persecution....er...percussion. Anyway, the fella had a large square of old kitchen linoleum...about 18inch square...that he held on either side and "waffled" on....called it..actually...a "waffle board". Made a great "woompa woompa" sound and was particularly effective on that old gem "Tie Me Kangaroo Down Sport".