The prop dustcover for "Gray's Sports Almanac" from Back to the Future Pt II (1989) includes SLAMBALL (basketball with trampolines) as a major sport, altho in 1989 it was only played in
Gray's Sports Almanac Back to the Future Replica / Kindle / iPad / Tablet Cover / Journal - Geekify Inc
Back to the Future Part II Grays Sports Almanac softcover notebook – Back to the Future™