if you have any hobbies or ideas for children let me know.
I second this idea:
Legos!!! Legos are amazing also!!! XD
I've seen quite a few children (including myself) enjoy building things.
Possible building toys include:
Legos or Duplos
Lincoln Logs
Wooden blocks
Outdoors: stacking bricks or rocks or sticks
Stacking cardboard boxes (empty or full). Kleenex boxes work well.
Building things with actual wood/nails/screws/glue
Minecraft on a computer
Playdough or Clay or playing with mud/dirt/sand
Wood train set (build track, drive train on it)
Electric train set (arrange track, watch train drive on it)
Things like jigsaw puzzles or sewing could also be considered "building" things if you stretch the meaning a bit.
If the kids are interested in sewing, you could have them try some easy projects (pillowcase for their bed, throw pillow for the couch, drawstring bag to hold something, stuffed toy snake, potholder for the kitchen.) Or you could let them have access to scrap fabric, make sure they know how to use the scissors and needles safely, and let them make whatever they want. Even if you think they are not doing a good job, they can learn a lot and have fun. That is why I recommend letting them have scrap fabric: if you do not feel that they are wasting "good" fabric, it is easier to sit back and let them do things their own way.