It consists of a scrollable grid of cells where you can allocate text. Cell contents can be edited interactively. It is also a container subclass, so it allows you to display buttons, curves, pixmaps and any other widget in it.
You can set attributes like border, foreground and background color and text justification.
GtkSheet comes with an extra set of useful widgets: GtkComboBox, GtkColorCombo and GtkBorderCombo. A demo program shows all of them interacting in a spreadsheet-like GUI.