Crosscut SledThis was my first serious jig, even though it's really pretty simple. I'd made a few drilling guides before this sled, but they were just scraps with holes in 'em. This one was a combination of parts that was a bit more complex. I don't know if there should be a distinction, but I make one anyway :-)
I started with a sheet of 1/2" particle board because it was what I had laying around. I also had some spare t-track that I got at last year's woodworking show. I believe it was this product from the Rockler booth. I destroyed a saw blade and risked my life ripping about 1/8" off the top of the track so it would "float" in a miter slot. I'll never do that again!
To that, I placed a 3/4"x3/4" length of scrap oak on the tail end as a fence. I put it in place with some panhead screws and oversized holes so I could adjust it for square once assembled.
This little sled works pretty good for 99% of my crosscuts. I also have a really excellent miter guage that I use quite a bit, too. Generally, if the stock is more than 4-5" wide or 2-3 feet long I'll use this sled. Otherwise I use the miter guage. I like this sled because it's got an edge that tells me exactly where the blade will go for the length of the cut.