fill the pool with water, soak 'em and have a bean supper fundraiser!
you can sprout/grow them and have a H - U - G- E Farm Sale or U-Pick
Beans can be harvested after 55 days, so you could have a couple crops
the beanbag/hackey sack idea is good too, beans absorb moisture, so keep them someplace dry or else they'll get soft & moldy.
that being said, the beans could be used as a doll body/sock monkey filler.
rain stick - use a piece of pvc pipe 18 - 24", drill random screws into the pipe (use power drill) - more screws, more "rain" sound - glue a pvc pipe cap on one end, put in some beans, glue a cap on the other end.You can use markers & decorate the rain stick. - sell them as a fundraiser item!
make a big mural, you can paint the beans in bright colours after - kinda like skittles!
-they make a nice texture
cover stuff with them - like a mirror frame, picture frames, keepsake box, glass jars - the dash of your car!
paint them with acrylic/tole paints or spray paint - to make them shiny and protected use clear acrylic spray