Marble Races with a cheap pool noodle (occupies the kids for hours.) Did this, but instead of cutting the pool noodle, the marble is small enough to fit inside the full noodle to roll down. Then can use the noodle for other things too!
Here's a fun way to use those noodles- a pool noodle water wall! Tons of fun, takes seconds to put together, can be set up in the bath or outside, and afterwards you still have in tact noodles to use for their intended purpose- THE POOL! by CrashFistFight