For the DIY marble run you'll need one pool noodle, some strips of blue painters tape (i.e. low tact), marbles and something to catch the marbles. Oh yeah, a stair railing is needed too, LOL.
Take the pool noodle and attach to the stair railing with tape. It's so light I only needed to attach it in two spaces (top and bottom). Put bowl at end of the noodle. Then drop marbles through the top of the noodle. I had all the materials at home so this took about 2 minutes to set-up, maybe less :)
This has been up for 4 days and all 3 kids play with it together every day. Lots of fun sibling bonding and making up of new games.