regular worms or crawlers are easy to keep, i have the same situation where i take kids out on a last minute basis. I bought a small plastic tote, filled it with peat moss and i keep crawlers and garden worms in there, i water it about once a week and feed them now and again, and they have lasted for months. I keep the tub in the basement covered. There is a ton of info an the web about how to do it. and really does save time and money, everytime i have bait leftover, it goes in the tub
http://whatcom.wsu.edu/ag/compost/easywormbin.htm
