I made a few new ones to replace some that didn't work well for my children.
Key MatchGo to a home improvement store and politely ask the key guy if you can dig through his discard bin. Choose as many keys as you can that have differently shaped heads. Gently place the keys on a photocopier and made a copy. Now you have a key matching activity. (You might want to wash the keys. They'll be pretty dirty.)
Lego PatternsMake some towers out of basic lego bricks. Form a pattern with the colors. Then draw pattern cards leaving the bottom block blank with a question mark inside. Take your towers back apart and toss the individual bricks and pattern cards into a bag.
Dry Erase Tracing CardsI printed some alphabet cards and some tracing activities and slid them into card protectors held together by rings (bought at Wal-mart). I stuck the set of dry erase tracing cards into a bag with some dry erase markers and a piece of felt for erasing.
Cutting and DrawingA pair of scissors, crayons, and some cutting and drawing activities from a book of reproducibles went into this new bag. They will just sort through the pile of activities until they find one they like and then go to it.
Organizationbusy bags.) I pull one from the front and when they're finished with the bag I move it to the back of the box. I keep one box at my feet so I can easily pull out another bag whenever one is requested.
I also made some lap trays lined with felt. Lots of the bags have multiple parts (beads, legos, keys, etc.) and they just open the bag and dump it into their tray. The felt keeps the small pieces from sliding around too much. This gives them some working/play space when they're buckled into their carseats. When they're done, they have to return all the parts to the bag before they can give it back.
The trays are also useful when feeding the kids in the car because they minimize crumbs and spills everywhere. I just pull out the felt during the meal and shake the crumbs out of the box and return the felt to the bottom after the meal.
If you like these activities, you may be interested in more.