Use your walls!
A Lego wall makes play possible without the need for a Lego table.
This metallic panel attached to the wall provides endless possibilities with magnets.
Compact, fun seating always works in children's areas.
Look for innovative options for seating in teen rooms, like these "Livingstones" cushions.
Below left is a window that teens can personalize with markers, making it their own.
Below right is a tiny teen space carved out beside a mezzanine railing at Salem (MA) Public Library.
Above is a pair of whiteboard tables that teens can draw on.
To the left is the Teen Room at the West Tisbury (MA) Free Public Library, with bright colors and flexible layout.