Hello, Bithead here, and us of the UNB play not only a single sandbox game, but a trio of sandbox games. Gentlemen, I give you, MINECRAFT(Terraria)!
THE SANDBOX GAME OF TOMARROW
FULLY CONFIGUABLE,
INFINITELY VARIBLE,
SAFE.
WILL ASSIST YOUR GAMERS EVERY STEP OF THE WAY.
I SAY TO YOU, WHEN LIFE GIVES YOU SANDBOX GAMES, DONT THROW 'EM AWAY! USE 'EM UNTIL YOU GET SO BORED OF THEM THAT YOU GET MORE THEN YOUR MONEY'S WORTH!
Now, time for nonportal2 rip off:
Buy Minecraft and/or Terraria. They are wonderful games.