Hardball Times has this article on cool HRs. The article says:
Actually, this is as good a place as any to commemorate the coolest home run ever hit. On July 25, 1956, a 21-year-old Roberto Clemente blasted an inside the park, walk-off grand slam to give the Pirates a 9-8 win over the Cubs. That might be the only such shot in MLB history. Coooool.
I never heard of this until now, but it is amazing! I would love if there was film/video of this some where.
Also interesting is the Bucs blew a 4 run lead giving up 7 runs in the 8th. They were down 8-5 in the bottom of the 9th. It looks like they loaded the bases with no outs, then "The Great One" lowered the boom.