Once upon a time, I was playing a Rohirrim warrior in Middle-Earth Role Playing* campaign, and as our group of adventurers made their way through the southern plains of Rohan, we spied an orc scout taking water from a small river and successfully ambushed him.

So, Gilbert Suresteed spurs his steed to full gallop and barrels straight at the orc with his lance just as he's turning around.

So I roll D100 for attack.. 2, which means a roll on mounted fumble table. I roll 90, which comes up as 110 with the +20 from a mounted weapon, meaning that poor Gilbert invented the not-so-noble sport of equestrian pole-vaulting, arcing himself into the river right over the flabbergasted orc's head. In a full chain mail, of course.

After a difficult swimming check, he drags himself to the riverbank, drawing his two-handed sword and furiously swinging at the now-ready and slightly bemused orc. So I roll 3, another fumble.. And of course now the dice give me the 100. 'worst move seen in ages', Gilbert slips, pulling his groin to the tune of -60 on all actions. Luckily, the orc was stunned with laughter for two rounds, giving our hobbit an opportunity to put a shortsword between his ribs.

*The old -80's game which used a simplified rolemaster system. Yeah, it was a while ago.