The man who invented the electric blender should be hailed as a saint. The reason? The motor on a cheap blender is loud enough (and hopefully sturdy enough) to instantly quiet any baby I've ever seen, and quite often lull them from a red-faced panic into sleep.

I'm running a blender at this very moment to quiet Ian, two months old with colic, who was up until five minutes ago screaming and crying because his mom had left and because his belly hurt. His pacifier just drooped out of his mouth, and he is dead asleep. Seriously, somebody could be doing dental work on this kid. Although I wouldn't recommend shutting off the blender until you're sure.

The only problem is that blenders aren't really designed to run 20-30 minutes at a time. While running one for 30 seconds and then stopping it will generally quiet the baby down momentarily, he or she will often get fussy soon after it is shut off. However, cheap blenders are often as low as $15, and often much much less at garage sales and the like. It doesn't have to be a $300 Bass-o-matic 5000 to quiet the kid down, and since noise is a plus it generally helps if it isn't.

As a side note, vacuums and white noise makers often work as well, but there's something about the tone and level of a blender that seems to work better for me.