I do so love thrift stores. I found another great game at my favorite Tampa thrift store: Second Image on Kennedy.
Quoridor is a strategy game played on a 9 x 9 space wooden board. The object of the game is to get your single pawn from its starting position at the center of your home row across the board to your opponent's home row.
The challenge of the game comes from the fact that each player has 10 walls, each able to cut off movement between any two pairs of spaces. Players either move their pawns or place a wall on the board. Walls can either be placed so they impede an opponent's movement or aid that of the player placing them.
It's a variation on a build-a-board game in that the static board is changed with the placement of every wall, so the field of play is ever-changing, and no two games ever end up being played on the same field.
A quick Google search brings up a few games from $23 to $30, though I'm sure you can find it for less--Second Image came through for me with a can't-beat-it $2 price tag.
So keep checking those thrift stores--they're a great place to find fun games to play between your duels in the Nature Dome!
Check out some great pics of Quoridor on BoardGames.com: http://www.boardgamegeek.com/boardgame/624