Jean Van de Velde at the British
Clemens back when he was with Bos blew a 10 run lead against NYY
Oilers v. Bills playoff game
Blazers v. Lakers game 7
Red Sox blowing 14 game August lead to NYY in 1978
Phillies lost something like 10 of last 12 to blow an 8 or so game lead in 1964 (I think)
Cubs blowing huge lead to NYM in 1969
Greg Norman at the Masters to Faldo, entered up 4 or 5 strokes ended up losing by like 4 or 5.