The ornamental design for a boardgame, as shown and described.
FIG. 1 is a top plan view of a board game, showing my new design; and,
FIG. 2 is a perspective view thereof.
The broken line showing of the numbers in FIG. 1 is for illustrative purposes only, merely disclosing that numbers may be used, and forms no part of the claimed design. The broken line showing of the thickness in FIG. 2 is for illustrative purposes only and forms no part of the claimed design. The shading in FIGS. 1 and 2 is not representative of a specific color, rather it illustrates a color pattern, i.e. similarly shaded areas are the same color.