Catching night crawlers (Lumbricus terrestris) is a fun wholesome activity that the whole family is sure to enjoy. OK....so maybe not. As night crawlers are huge slimy earthworms that come out of lawns at night, I really doubt that the WHOLE family will like it, but I'll be the 8 year old boy population would. Night crawlers are used for fishing bait, and are the preferred lure for trout fishermen in many parts of the world. Here's the scoop on how to catch night crawlers.
A well watered lawn is more likely to entice the worms to come out after dark. Wait until about a half hour after full dark, and walk lightly out onto your lawn with a flashlight. Hopefully you will see the tell tale glisten of your light off a night crawlers body. You have to be quick at grabbing the slippery fellow, or he'll try to go back in his hole. If he does succeed in making it partially back into his hole, it is very difficult to pull him out without breaking him in two. If you apply just the right amount of pressure, he will give up before you do and you'll be successful in catching a night crawler.
Night crawlers can be kept alive in the refrigerator for a week or so, provided they have something to keep them from drying out. It is a very good idea to label the container clearly, as some members of the family respond negatively to opening a container expecting leftovers and finding a cluster of slimy worms.
I hesitate to even mention this, as it's clearly cheating, and a method of worm hunting that only extremely unscrupulous people resort to, but there is an alternate method of capturing night crawlers. Some people use cattle prods or electrical devices to force the poor helpless night crawlers out of the ground and stun them, making them easy to gather. This is clearly a violation of worm hunter ethics and is frowned upon by serious worm gatherers all over the world, but it is a fact of life, and ugly as it seems, needed to be mentioned here.