When your children need inspiration for an activity, they draw two or three papers and then decide which idea they want to do, either as a group or individually. If you want some ideas that other kids have written, a "boredom busting activity ideas" list is available.
It’s not your job to entertain your kids all the time. It’s their job to figure out how they would like to use their time in constructive ways. By giving them freedom within limits, you can help them develop new skills and find ways to enjoy themselves without having to be entertained by some outside entity. Developing this ability will serve them well thorough out their lives.