If you're a longtime lover of castle building series Stronghold, you'll be very happy to know you can download an HD upgrade for Stronghold, Stronghold Crusader, and Stronghold Crusader Extreme right now, free of charge.
The free part is assuming you already own copies of the games, of course. If you don't, though, they're all on sale right now on GOG, Amazon, GetGames, and DotEmu -- on GOG at least, Stronghold is about $5, while Crusader is $8.
The upgrade itself appears to simply up the max resolution allowed, but does make a significant difference, especially because you can now view the whole map at once. Previously the max res was 1024x768; now you can go up to 2560x1600.
The patch is available now on GOG I believe -- not sure about other shops. If you have another version of the game or plan on getting one, you can grab the patches at the source, if necessary.