Yes, I know this is a stupid question, but many people here in Greece have said this to me. Basically, the story goes that during WWII, Greek soldiers would throw bed sheets in front of tank tracks or straight at them so they would get sucked up inside them. This would cause a jam and stop the track from moving, making it an easier target. Is there any way this could be true?
The short answer is no. The long answer is stranger things have been tried.
First, blankets. It's true that blankets were suggested as an anti-tank weapon, but only in the most desperate of times. A British Home Guard anti-tank team would use a blanket in the following fashion. Two men would take a blanket wrapped around a rail, and jam it into tank tracks. A third would douse the blanket in gasoline, and the fourth would throw a match, igniting it. Thankfully, the Home Guard was never called upon to fight any German tanks, and the doubtful value of this technique was never tested. As a rule, trying to shove things into tank tracks was rather ineffective.
A soldier named Loimu tried to stop a Soviet tank with a crowbar. With a fearsome screech, the crowbar rotated around the track and fell out, causing no damage. Next Loimu tried a thick log. The log "turned into a heap of toothpicks that was enough to supply a company, and the tank kept driving along until it was blown up with a bundle of grenades."
The Soviet Partisan's Companion, a guidebook for resistance fighters who rarely had access to real anti-tank weapons, doesn't suggest any kind of ridiculous suicidal tactics like that. Tanks can be fought by trapping them in a deep pit or tricking them into falling through artificially weakened ice into a lake or a river. In the winter, you can also cover a slope in layers of snow and ice so that a tank is unable to gain any traction on it and slips downhill. Of course, if real weapons are available (armour piercing bullets, grenades, or Molotov Cocktails), those should be used.
Sources:
A. Ulanov, Antitank Exotics: Trap, Scrap, and Hammer