With your feet being arguably the smelliest part of your post-workout body, it's a shame (especially for those working out next to you) that they almost never get washed. Or is that just at my house? In any event, while tossing them in the washer and dryer is a quick fix, you can spare your sneaks and lengthen their life with a little bit of care.
First, laces can go right in the washer with your clothes, but be sure to line dry them unless you want them to shrivel up and die in the lint basket. Next, unless your sneakers are advertised as washable, don't throw them in the machine. Just take a sturdy cloth (like an old towel) or scrub brush and after removing the inserts, scrub the heck out of them, inside and out with warm, soapy water. Stuff them with newspapers, let them air dry completely and reinsert the insoles and laces. Voila!
To keep them ultra-fresh, after your workouts, don't throw them in the bottom of your closet where they're unlikely to dry completely. Set them out in a well-ventilated place to dry and sprinkle occasionally with our best friend, baking soda.
Hot Tip** I also like to keep a small sheet of scented fabric softener in them when I travel to keep them fresh (we all hate that damp musty smell!) in transit.