If a place is stageful, it has a lot of things happening or a lot of people there, like a stage with many actors or a room with many people.
Stageful can make people think of excitement, busyness, or a lot of action.
Examples:
The theater was stageful with all the actors and props.
The party was stageful with so many people dancing and talking.
The classroom was stageful with all the students working on their projects.
The playground was stageful with kids running and playing everywhere.
The city was stageful with lights and noise all night long.
The zoo was stageful with animals and people watching them.