Honestly? Rice Krispie treats are best the same day. You can keep them from getting too hard by really sealing them well with Saran Wrap and keeping them air-tight and they will be ok for 2-3 days but they are just so much better-textured the same day.
I made some for Childrens Church last weekend (Easter) and cut them out into a flower shape. DH and I had a plate full of scraps to polish off! I made them Saturday night and they were still good on Tuesday afternoon. I tossed the little bit that was left on Wednesday though. They were petrified little Krispies! I just covered them with saran wrap.
I've kept them stored in a plastic container or covered with plastic wrap for up to a week.
I pop them in the microwave and heat them up for about 20 seconds on power level 6 or 7 and it mushes them back to that "just made" stage.
Hmm..think I feel a craving coming on...
Tact is telling someone where to go so nicely they can't wait to take the trip!
I'm with SC on the "they are best the same day" thing, but if you wrapped them really well with plastic wrap and then put them in a container with a lid, maybe a couple of days. The microwave thing might work too, I'll have to try it!
"Love is grand, but all I really need is chocolate." -Miss Piggy