A hi-res version of the Sample Dungeon map included in the 5th edition release of the D&D Dungeon Master's Guide.
In one simple download you get both the DM and players versions of the map as well as an un-gridded rendering that's perfect for use with any virtual tabletop software. Sized at 3287 x 4500 pixels, it's perfect for home printing or screen display. Purchase it now to help run the DMG's sample adventure or use it with your own stories and home-brew campaigns.
P.S. For a quick and easy tutorial on resizing digital battle maps for printing and use with miniatures, make sure to visit Schley's Tutorials.