Let's start with a Dell Inspiron 7000 laptop that I owned for about 6 years. I don't know the exact specs, but it was running GNU/Linux and everything except the battery worked. I posted it on Craigslist - I got 15 "I'll take its" in 10 minutes. The guy picked it up the next day for his ten year old daughter to use. I felt great.
Next one; ten circa-1992 Thinnet repeaters with BNC connectors. For those not on the floor laughing, nowadays these are about as useful as shouting "One!" and "Zero!" into two tin cans with a string between them. Posted on Freecycle and gone in 30 minutes, to a guy right down the street from me. He needed then to run some old system that was still in use.
Sailboat. This is no joke; Freecycle lets people asks for items as well, so one guy asked for a sailboat for his family to cruise around in. After taking considerable flak from the rest of the group for asking for such a 'luxurious' item, he got it! A week later, a guy offered a 14-foot sailboat that needed work, had a trailer with two flat tires, and he just wanted the thing out of his yard.
Finally, a 500 pound server; this one is my favorite. This thing was huge - three feet high, two feet wide, two feet deep - and solid metal. It took three men to move it with a handtruck. There were dozens of hard drives, backup power supplies - the works - but it was old. We had tried for over a year to get rid of it; it sat in the main hallway, sometimes being used as a table. Then I posted it on Freecycle.
Gone. In under a minute, to a guy that wanted to run an Internet site. He picked it up that day.
[one more, just got rid of a broken coffee maker using Craigslist in half an hour! Mark]