SQUIRRELS:6, ME:0
It seemed like a simple job. I have a bird feeder on a 6ft. post that I was installing in the front yard 2 houses ago. At 5 every night, my wife and I played backgammon while drinking wine on the screened front porch prior to dinner. And, within several 
days during that time, I realized that the squirrels were able to get to the feeding platform given the rapid reduction in birdseed. At first I figured that they were able to climb the 4x4 wooden post. So I purchased an 18-inch metal tube that was placed over the post. It was fitted loosely so that when the squirrel attempted to climb on it, it would swivel. Presumably, the squirrel's claws would not be able to keep a grip to move upward. However, within several days, I realized that the 'solution' was not successful, but for another reason it turned out. Looking back on the 'solutions' that were yet to follow, I started the count as: Squirrels:1, Me:0,
Within a week, the reason for the reduction in birdseed was that one of squirrels had managed to leap from the tree to the to of the feeder. With an easy climb down, it was into the birdseed. Also to my horror, it proceeded to brush bird food onto the ground, presumably for its less athletic comrades. My feeder had turned into a 'socialist squirrel feeder'. Don't misjudge me please. I don't mind feeding squirrels. But this was premium bird food meant for birds, and the squirrels were jeopardizing that significantly. What to do? What to do? Now the count was: Squirrels:2, Me:0
My next 'solution' came to me slowly, I admit. I am an amateur woodworker with numerous tools that exceed that required by the normal amateur. (Every new project justifies a new tool). I went to my workshop and looked for material that could provide a 'solution'. In the corner there was piece of plexiglas remaining from a frame that I had created for a picture. 'That's it!', I said out loud. I cut a rectangular piece that was 12 inches high to attach to the tree-side of the feeder that didn't interfere with our view of the feeder from the front porch. Surely, it would prevent a squirrel from jumping from the tree to the top of the feeder. WRONG!. That piece of plexiglas simply provided a higher, even closer, landing point for the squirrel to get to the birdseed. Squirrels:3, Me:0
OK!, This was getting ridiculous, if not pathetic on my part. After all, I have a BS in engineering, albeit in Metallurgy. But nonetheless, I should be able to outdo these squirrels. So!, the heightened landing strip didn't work. And then I thought, what about a heightened surface upon which they shouldn't be able to land? Please understand that I am not a malicious individual. But yet, the squirrels had now the better of me. That is, they had too far challenged my belief in my intelligence. It was time 
to become, perhaps, more aggressive in my 'solution". Again, back to my workshop for possibilities. There it was in the corner. There was this rake that I would never use again. (We can now afford professional gardeners.) In my opinion, attaching the working end of the rake to the top of the bird feeder would be an impossible landing position for the squirrels. With minimal effort I was able to attach the rake's prongs in addition to the plexiglas. Any concerns of a squirrel shredding itself as it went through the rake's prongs were short-lived. The next night on the porch, I saw a squirrel land on the top of the rake's prongs and then down to the birdseed. Squirrels:4, Me:0
In several months, we moved to a new house. The backyard had no trees near where I installed the feeder. Hence, I removed the rake prongs and plexi-glass. I thought the original metal cylinder attached to the post would deter the new set of squirrels. WRONG! With an amazing, perhaps accidental, coordination between two of the squirrels, one had crawled up inside the cylinder, hence preventing the cylinder's swivel. At that point, another squirrel was able to move up the cylinder fast enough to make it to the feeding platform. Squirrels:5, Me:0
For the next 2 years or so at that house, I didn't notice any further successful, coordinated attempts with 2 squirrels. However, at the end of that period, we had the opportunity to buy a phenomenal house, with a pool no less, and make a significant profit on the other house. On the far side of the pool there are two large palm trees approximately 30 feet apart. I placed the bird feeder half way between the two trees with total comfort that the squirrels could not jump from either one to the bird feeder. Therefore, I was comfortable that the cylinder would be a sufficient deterrent. WRONG! Within 3 days of filling the feeder with bird seed, at least one Olympian squirrel had found it possible to tackle the cylinder in a single bounce and then onto the food platform. Squirrels:6, Me:0
NO! I am not giving up yet. I have one more idea. However, I am posting this story at this point. I will update it later as to the new score once my forthcoming idea is applied.
Perhaps to be added at some point is an idea I have to make a challenging (yeah, right) obstacle course for the squirrels. My hope is that such a course will be partially covered on one side with plexiglas for our entertainment. To regain some engineering respect for myself, I will plan a modular course that can be rearranged each time it is conquered by the squirrels.