Is it a snack? Is it a game? Is it educational? Yes, yes, and YES!
I almost feel guilty calling this an "activity" as it's so easy but it's saved me many, many times when I "needed" some peace and quiet to enjoy a cup of tea. I tried to come up with a catchy name but finally decided to call it the wildly creative name that my kids call it: Cheerio Spaghetti Playdough because...well, that's what you need to have to do it: cheerios, uncooked spaghetti, and some playdough. Oh, and 20 minutes to an hour's worth of time (depending on their concentration level) for the kids to play.
Squish a glob of playdough on a table, stick a few strands of uncooked spaghetti in it, then hand over a bowl of dry cheerios. Show them how to thread the Cheerios one by one onto the spaghetti, then sit back and enjoy your tea/coffee/mimosa (not judging).
Miss M (four and a half years old) carefully threaded each Cheerio on until all four strands of spaghetti were full, then carefully picked each one back off and ate it. She was able to thread them relatively easily and had fun building her towers of Cheerios. She also followed the "rules" and didn't eat her Cheerios until she'd threaded them all on.
Now Mr M (two and a half years old) started by shoving a handful of Cheerios in his mouth, then he would thread a few on on, then pick them off and eat them; then he would start all over. It was harder for him and his chubby little fingers so sometimes he needed to use both hands to balance the Cheerio on the piece of spaghetti to line up the hole.
It may be a ridiculously easy activity, but it is actually awesome practice for hand-eye coordination and fine motor skills. We threw in some counting as well to make it even more educational.
When they had eaten all the Cheerios I let them play with the playdough to extend the peace and quiet, er, the learning I mean. This is a treat in itself as this Mama doesn't bring out the playdough that often (those dried bits all over the place drive me bonkers, especially when they show up in rugs or the furniture).
Hooray for easy, self-managed activities that kids learn from too!