(who is now blind) would feel thetops of his sheep as they left the cave, in order to make sure that the men were not riding them out or trying to sneak out beside them, is particularly impressive. Knowing the Cyclops would do this, Odysseus lashes three sheep together and secures one man underneath them so that when Polyphemus feels the sheep's backs, he only feels wool (with the men hidden well underneath). Further, his realization that they must incapacitate but not kill Polyphemus evidences some pretty sound judgment as well. The relatively small men need Polyphemus to roll aside the stone in front of the cave's door, or they will be trapped inside until they eventually starve to death. All in all, Odysseus's plan goes remarkably well; it is when he does something that he does not plan on—mock the monster he just blinded—that things start to go wrong.

Given the circumstances, the plan appears to be pretty solid to me.  Given that there literally was no way for them to simply sneak past him, their plan to use the sheep hides as a way of tricking him into thinking that they are the sheep and will allow them out after he moves the stone, important since they cannot move the stone themselves.

Of course the additional part of the plot in making sure that they had referred to themselves as "nobody" became aparticularly vital once they had escaped fromo the cave and Polyphemus was calling for help.

The only part that was clearly stupid, wasn't necessarily part of the plan but when Odysseus decided he ought to taunt Polyphemus, he invited disaster.

Returning from the Trojan War, Odysseus and his men stop off at an island where Cyclopes, one-eyed giants, live. They take refuge in a cave, only to learn that it is the home of one of the monsters, Polyphemus. The creature rolls a stone over the door, trapping the men, and begins eating two of them each night. During the day, while the giant is gone, Odysseus and his remaining men sharpen the trunk of an olive tree into a spike. That night Odysseus offers the giant wine so he will sleep soundly. In a drunken state, Polyphemus asks Odysseus his name, and he replies, "My name is Nobody."

While the Cyclops is asleep that night, the men climb onto his chest and drive the spike into Polyphemus's eye, blinding him. The Cyclops calls out for help to his brothers. They rush to the cave and shout back, asking him what is wrong. He replies, "Nobody is hurting me," so his brothers leave without helping.

Even though he is now blind, the giant is still a threat because he keeps the men imprisoned in the cave by rolling the stone across the door every day when he brings his sheep to pasture. He pats them on the back as they exit the cave to make sure the men aren't riding the sheep. After observing this, the men figure out a way to outsmart Polyphemus. The next time he opens the cave to let the sheep out, they cling to the underbellies of the animals. Though Polyphemus pats each seep, he does not detect the stowaways. They flee to their ship, and Odysseus calls back, "I'm not Nobody. I'm Odysseus."

Odysseus' escape from the Cyclops Polyphemus is a rather humorous one (and one that ends up causing problems for Odysseus later). When Odysseus and his men find themselves trapped in the cave of the Cyclops, being eaten two at a time, they come up with this plan: Odysseus gives Polyphemus some undiluted wine, which he had been given earlier in the trip. Polyphemus becomes drunk from the strength of the wine, and when he asks Odysseus for his name, Odysseus responds with, "Nobody," so Polyphemus promises to eat "Nobody" last, after eating all the others. Once Polyphemus is unconscious from the wine, Odysseus shoves a sharpened, hardened stake into the Cyclops' eye, effectively blinding him. The Cyclops then stumbles about, shouting that "Nobody" had blinded him, and the other Cyclops thought it was divine punishment, so they recommended that he pray for forgiveness. The next morning, Odysseus and his men tie themselves to the underside of Polyphemus' sheep and are set free when Polyphemus lets them out to graze. When they finally reach their ship, Odysseus tells Polyphemus his real name, so Polyphemus prays to his father, Poseidon, to avenge him.

This incident serves to demonstrate several traits of Odysseus and, despite its brutality, is a favorite in his quest to return home.  It shows his concern and protective loyalty to his soldiers, and his unselfishness even in his strong desire to return to Ithaca.  But primarily it shows his cleverness, inventiveness, intelligence – an important character trait and a “weapon” he uses as a warrior (contrasted with the brute strength of Ajax, for example; he demonstrates his understanding of “how the world works” in that he foresees Polyphemus’ reaction, his weakness, his priorities, his “blindness” (not just ocular but in not guessing at the presence of the soldiers under the sheep).    

I think Odysseus's plan to escape Polyphemus is pretty ingenious.  He first considers killing the Cyclops by stabbing him in the liver while he sleeps, but then Odysseus correctly realizes that they need Polyphemus to roll the stone away from the door because it is too big for his crew to move.  If he kills the monster, there will be no one to let them out of the cave and they will all perish.  Despite the danger they're in, Odysseus still exercises rationality and forethought and cunning.

Therefore, when Odysseus comes up with the idea to blind Polyphemus so that he can still roll away the stone door, it is quite shrewd and intelligent.  He gets the monster really drunk, he and his men plunge an olive stake into his one eye, and then they ride out of the cave tied underneath the sheep so that Polyphemus will not be able to feel them.  Further, Odysseus had told Polyphemus that his name was "No man," so that when other Cyclopes came to check on him, he would have to tell them that No man had hurt him.  Hearing this, they left him alone. 

Finally, the plan succeeds, and all but the six men Polyphemus ate escape the cave, so it must have been pretty sound!