A mortise and tenon is an extremely sturdy and strong way to join wooden furniture. A recess is created in one member (mortise) that allows a protruding tongue from the other (tenon) to fit tightly inside. There's no better way to assemble table bases, chairs, benches, and even frames.
Except, mortises can take a serious amount of work to cut. Unless you have a dedicated mortising machine, you're in for lots of time with a chisel and mallet, especially on large mortises like the one shown above.
Woodsmith magazine came up with this clever solution to cut the time significantly. (At least 75% saving by my guess). This would be particularly useful on mortises designed for large cross members, like a workbench or big dining table. The answer: cut the mortise with a table saw.
How's it work? Well, the leg needs to be in two pieces, and then it's cut before being glued to make a solid leg. Anything that's that beefy is likely going to need to be made from a glued up block anyway, so you can save yourself lots of time. Of course, this will only work with a through mortise, where the tenon goes all the way through instead of being buried inside, but that looks cooler anyway.
I wish I'd known about this when I built my workbench. Check out the full technique from Woodsmith: Cut a Mortise on the Table Saw